I’ve been on Debian Testing for my own desktops for about 15 years now. Sometimes as a Frankendebian mixing in SID/unstable. Sometimes mainly unstable, but mostly just Testing.
It rarely breaks, but when it does, it’s a learning opportunity. Stable for servers and other people’s desktops. Maybe with backports. Flatpacks if this no other option.
You don’t get 100% solid and 100% new. Ever. With anything.