If its a mission critical use, I would stick to a more common TLD (com, org, net, etc). Country TLDs should be okay too.

Just use open source software?

I’m currently switching all my computing/cloud stuff over to Canadian and/or EU providers. I’m going to move my domains to Easy DNS and try out a VPS from LunaNode.

I did this and used PostmarketOS for about a month before reinstalling LineageOS. Biggest problem for me was the lack of Camera. If you have a second device running android or iOS then it is a fun idea, but not really practical as a main device.