Firefox offers better privacy and security than Chrome, with upcoming support for 200 new add-ons.
Also built in spyware and a LOT of snitching to a 3rd party analytics company that can be disable in flags.
If you're serious about privacy use LibreWolf or Ungoogled Chromium if you're reasons that required the Chromium dev tools.
The future of selfhosted services might includes phones yes, Android most likely not.
Think about it, those phones might work right now but in 10 years their Android versions will not support anything, they wont even have root certificate updates breaking SSL, the kernel will be missing support for whatever people need and whatnot. Maybe the phones won't even boot because some key will expire somewhere... let alone security vulnerabilities.
People selfhost on 10-year old hardware right now, but they do install modern Linux distros that are well supported and up to date. I believe the most likely scenario is that at some point the "security" of most of that hardware will be broken and you'll be able to run some version of AOSP for older hardware and/or a generic Linux.
But that might not ever happen, those phones are built like hell and we've another category of hardware with similar characteristics that was never repurposed for anything after a decade - routers. It's common to see older routers that are now too slow when it comes to wifi or even CPU and although they're way more open and primitive than modern smartphones when it comes to software we usually can't even repurpose them as dumb switches with alternative / open software. OpenWRT and DD-WRT might work in some case but those are exceptions and usually those models were already supported by those firmwares. For instance there are enough Thomson / Technicolor TG784n ISP provided routers to create a second moon and the effort to break their security and create a usual firmware is so much that nobody did it. It's just easier to pay 30€ for a cheap router/switch and move on.
Furthermore depending on your ISP you might be able to simply add a small ARM box attached to it and use ir for DHCP, VPN, DNS resolver etc. and you could still use the ISP router as gateway / firewall / switch / wifi.
How much wifi and open-source do you really want?
If you are willing to go with commercial hardware + open source firmware (OpenWRT) you might want to check the table of hardware of OpenWrt at https://openwrt.org/toh/views/toh_available_16128_ax-wifi and https://openwrt.org/toh/views/toh_available_864_ac-wifi. One solid pick for the future might be the Netgear WAX2* line. One of those models is now fully supported the others are on the way. If you don't mind having older wifi a Netgear R7800 is solid.
If you want full open-source hardware and software you need a more exotic brand like this https://www.banana-pi.org/en/bananapi-router/.
Both solutions will lead to OpenWRT when it comes to software, it is better than any commercial firmware but there's a catch about open-source wifi. The best performing wifi chips are Broadcom and those don't usually see open-source software support**. MediaTek is the open-source alternative and while they work fine they can't, unfortunately, beat Broadcom. As most hardware is Broadcom they have hacks that go behind the published wifi standards and get it go a few megabytes/second faster and/or improve the range a bit.
** DD-WRT is another "open-source" firmware that has a specific agreement with Broadcom to allow them to use their proprietary drivers and distribute them as blob with their firmware. While it works don't expect compatibility with newer hardware nor a bug free solution like OpenWRT is.
Blockchain and/or smart contracts try to solve problems that were already solved in multiple ways by adding a ton of overhead that makes them unable for large scale deployment and long term usage.
Here's what's stupid about the people who say that blockchain will revolutionize the financial sector: why add a blockchain and all the computing power to store transactions when you can take the obviously efficient route and simply store transactions on a SQL database? Before anyone screams the word "decentralization" do you really think banks will cease to exist? NO. The most likely scenario - if people keep pushing this bullshit - will be to have some kind of closed blockchain that banks use to transact money, so it essentially becomes the same thing we've now with added overhead, environmental impact and technical complexity. We have efficient system in place with safeguards, operations can be tracked, reversed etc.
Frankly it would be a better use of everyone's time, money and effort to simply fix the REAL problems in the banking industry, such as the fact that the US still doesn't have a decently working, standardized digital system to transfer money between account holders in different banks. Europe has this with SWIFT/IBAN and people can transfer money between accounts, banks and countries almost instantly by just providing the amount they want to transfer and an IBAN number (nothing else required). Now tell me, how many people in the US have bank account with IBAN numbers? Most likely only millionaires. The majority of people use a combination of poorly structured system of account and routing numbers that often fail and lead to delays. Oh btw Russia has a similar system to IBAN.
There are tons of other weaknesses in the US banking system around the way credit and debit cards work, for instance why would anyone on their right mind assume that a system where you can provide your credit cards number and CVV/CVC code over a phone to make a transfer wouln't be abused to scam people and steal money? Then, after decades of fraud, to "alleviate" the issue they decided to create a bunch of companies that offer virtual credit cards with limits. Now let this how with works in most European countries: banks will, most likely, refuse any attempt at charging a physical credit card unless its made on a physical payment terminal with the card actually physical inserted on the thing an a 4 digit PIN code typed in. If you want to buy shit over the internet simply open your bank's app or website and they'll have a function to create a single use virtual credit card for the transaction. Way more secure isn't it? :) Either way most European countries also other systems to handle those kinds of payments eg. the online stores provides you with a specific code and you then can go into any ATM or your Bank's App, insert the code and make the payment.
As you can see making the banking system efficient and having fast, secure and usable things isn't about blockchain bullshit, its usually more about common sense and creating standards that companies, such as banks, have to comply with.
Yes, you can use a Cloudflare tunnel but why? Since you're into self-hosting why should you depend on some random company to tunnel your traffic when you most likely don't need it? You also have all the potential tracking, spyware, risks and "being hostage" scenarios that may come with that choice.
The following assumes your use case is a simple home server for "standard arr apps, jellyfin, pi-hole" for personal usage that sits inside your network and your objetive is to be able to access those services. If you're instead trying to host a game server / few services for friends (that doesn't really need to be "inside" your home network) there's a more complete comment with other security considerations and recommendations here.
Your basic requirements are:
Quick setup guide and checklist:
Since you're only allowing access to your services through the VPN and you've heavily restricted access to the VPN port you'll be safe. Just a side note, don't be afraid to expose the Wireguard port because if someone tried to connect and they don't authenticate with the right key the server will silently drop the packets.
Now if your ISP doesn't provide you with a public IP / port forwarding abilities you may want to read this in order to find why you should avoid Cloudflare and how to setup and alternative / more private solution.