There's a pile of reverse proxies out there, NPM is one that's built on nginx's reverse proxy mechanism that's a little opaque to configure if you aren't much for text configuration files. I do like it for quick and easy LetsEncrypt SSL cert management, and it's integration with Certbot, especially when you have LE moving to very short SSL lifetimes. This can all be done manually with cronjobs etc, but NPM is pretty low effort and works well.
Other reverse proxies that use their own engines are Traefik, Caddy and HAProxy. They each have their use cases, such as docker integration or high availability. None are as easy to use as NPM in my opinion.
Gnome and Plasma both recognize 4K, or should. So Plasma has a builtin RDP server you can enable in settings, which connects to the console session every time. I'm not sure if I would call it rock-solid, but it's not terrible for remote work, and usually it's the shit internet connection that gives me trouble.
Using Xfreerdp client or Remmina from linux boxes seems to be as good as the RDP clients get, and I don't generally see any issue with it. If I remote into one of my boxes with the plasma RDP session enabled, I see both monitors at their running resolutions in the RDP client. I'm using Krdc as a client, but it's maybe a bit flaky as a client which is why I recommend the others.
Kubuntu is a buggy mess every time I've tried it over the last decade, which is probably half a dozen times. Pretty much anything else seems to handle Plasma fine, Fedora has been the least hassle one of the lot. And I've used Linux for over 25 years.
Well, considering your search history will now be associated to a IRL payment method, you hope they're trustworthy, but I think we know how that goes these days.
Or jump through the hoops to use an untraceable cryptocoin to pay.
Maybe he's just worried about getting Kirked.