Yes, RaspiOS is based off debian and is the default OS that people usually use on a RPi. If you have a monitor, usb keyboard and mouse at hand go for OS "with desktop" option, otherwise try "lite" (headless) version and you can control it from your pc/mac through SSH. Either way connect it to your router with a cable. There's plenty of online tutorials to help you getting it set up.

Usually routers by default assign different IPs to new devices each time the device connects. For your use case it would be better to tell your router that anytime it sees the RPi, it gives it the same (static) IP - so you can be sure where to find it later when Umbrel gets online. Again, google is your friend on how exactly you need to do that - it depends on the router model.

I'm sorry if this seems overly complicated, but if you can't get Umbrel up the easy way, you'll just need to figure out what is causing the problem. You might also try out Citadel/RaspiBlitz/Start9 or something similar to Umbrel first, but chances are you will get just as stuck with those.