Installation of OpenWRT from stock depends on the device. Some devices are more involved than others.
Updates are not automatic, and they require planning with some down time. The process is backup settings, update wiping out settings, reapply settings by uploading backup.
I do not install packages. That leads even more horribly complicated updates. I don’t recommend using anything that isn’t in the stock image.
LuCI is serviceable. It’s not pretty, or the most intuitive, but it works.
OPNsense is better if you have the x86 hardware around to run it.