You can do whatever you want. Don’t let anyone tell you it’s “wrong”. A big part of homelabbing is to try stuff. If it doesn’t work, that’s fine, you learned something, and that was the point.

For me, I don’t see a UPS as essential. It’s generally a good idea, but not strictly essential. My servers are on 24/7, because I have services that do things overnight for me. I also know that some people access my lab when I’m not awake, so I just leave it on so it can be ready for anything at any time. It poses some unique challenges sometimes when running stuff that’s basically 24/7/365.

Be safe, have fun, learn stuff.