I’m not sure what you mean by this. I had a look at the instructions here:
https://doc.owncloud.com/server/admin_manual/maintenance/manual_upgrade.html
It doesn’t look as easy as the Nextcloud updater, but at least I would have total control over updates. It seems control over updates is becoming an enterprise feature of Nextcloud, so I’m not sure I would chalk the Nextcloud update process up as a win for Nextcloud. I will have my Owncloud instance up and running later on today and will begin testing. It’s possible I will find that the update process is more cumbersome than I anticipate, but I have a hard time envisioning a scenario in which manually updating the server is more cumbersome than manually updating clients on user PCs.