Yeah, I keep getting myself blocked because of something I'm hosting is giving a lot of false positives. I suppose I'll have to dig into it at some point. For now I just whitelist the IPs I use.
There's a difference between privacy and anonymity. You can have privacy without anonymity. So, it's about what you want out of the app. If you're looking for anonymity then it's not the app for you, and there are other apps that can do that better.
Proton will so smtp if you're on one of the paying plans. You can get your own domain setup to use with it. This is what I do. I just had to contact them to get it setup, they ask a few questions about usage, which I just said was self hosting stuff and sending occasional emails.
For my use case, I can't get it to autoplay the next podcast. I would need to setup a playlist or something. The Web version does this just fine, just not the app. I've been playing with Absorb and that seems to do this, though in Android Auto mode it breaks occasionally. Can't speak for this app. Maybe I'll try it and see.
I've found that if I set primary as pihole and secondary as, say 1.1.1.1. then, my android phone will pick either one seemingly randomly. So my local DNS doesn't work.
My workaround was to do two pihole. I forget how I sync them though.
You can get an updated modem from Nissan if you wanted. My boss did that, but I don't remember the cost.