I'm not familiar with what's been said or done regarding bots, but I'd be surprised if they were planning to shutdown the self-hosting part? But I can see how they might shutdown the free cloud auth aspect.

As RD consists of the server/client software and the authentication software, the latter is also made available online to all with no reliability promises. But there's nothing stopping people from hosting both parts locally, and is how I implemented it. No traffic to third parties, etc.

Can't advise on domain-based setup, as I've not tried it, but depending on how you're planning to use it, there may be no need for a domain. I only used mine locally (or via WireGuard when outside), with hbbr and hbbs hosted in Docker on my NAS, and it worked fine with my mobile devices and PCs.