I encounter the same problem. It stuck on the same point for the update. I’m on a shared host, too. But until now i never had problems with updates.
I hope get it managed by trying it several times 
EDIT:
Could this help here? https://help.nextcloud.com/t/fehler-nach-update-auf-12-0-1/19229/7
I do not understand what the solution does, but i cloud try it…
EDIT2:
Ok, I can’t, because there is nothing like /nextcloud/apps/files_accesscontrol/lib/Operation.php in my Installation. Seems like something very different…