Another vote for Aurora.
Universal Blue in general has been really solid, I remember one time in the last year or two when there's been any need for manual intervention. And that came with a notification after boot, with a link to instructions that were all copy-pastable as-is to the terminal.
My biased opinion is that most people run Nextcloud on an underpowered platform, and/or they install and enable every possible addon. Many also skip some important configurations.
If you run NC on a bit more powerful machine, like a used USFF PC, with a good link to it, the experience is better than e.g. OneDrive.
Another thing is, people say "Nextcloud does too much", but a default installation really doesn't do much more than files. If you add every imaginable app, sure it slows down and gets buggy. Disable everything you don't need, and the experience gets much better. You can disable even the built-in Photos app if you don't need it.
Not saying NC is a speed daemon, but it really is OK. The desktop and mobile clients don't get enough love, that's true.
I'm talking about the "bare metal" installation or the community Apache/FPM container images. AIO seems to be a hot mess, and does just about everything a container shouldn't be doing, but that's just my opinion.
I'm not sure if this is of any help, but I had the same issue with Wake on LAN enabled. This was a while ago with an Asus motherboard.
If you don't need WoL, disable it and it should fix it if your MB is affected.
But if you do need WoL, look at https://wiki.archlinux.org/title/Wake-on-LAN.
The section 5.2.2 Fix by kernel quirks was what fixed it for me.