Be aware there are basically two different things called Owncloud. There’s still the original php version, which is similar to nextcloud but worse (not open source, smaller plugin ecosystem I think)

On the other hand is owncloud “infinite scale” (or ocis). This is the thing entirely written in go. But as others have pointed out, it’s little more than a file server at this point.

IMO the self-hosting community is really missing a self-contained “all the DAVs” server (files, calendar, contacts). Baikal etc seem like a great start, but it would be great to have somewhere to get those parts pre-assembled. Until then, nextcloud works for me.