I've been using Nextcloud for years and it has never performed well but I always put that down to my disks being slow.
It has gotten quicker over time, but not hugely.
I rarely use the web interface, I just use the mobile app to sync photos from my phone then everything on my network runs over NFS. It even that was a pain to get working with permissions with NC.
Now I want to try OC. I think the reason I went with NC was because it was meant to be the new and better developed OC after a bunch of OC devs left to form NC.
I'm not as advanced a user as you so clearly are. But when I looked at Garuda they insisted you use btrfs and had no option for anything else. Well fuck that shit. I'm not touching that horror show of a file system again. Why does it have to be so opinionated to force one specific file system. Nonsense.