I have tried nextcloud on R7800, the locale problem is fine for me, it has easy workaround.
The reason I decided to drop nextcloud on R7800, is the problem with nextcloud autologin using router's login credential.
Each time nextcloud login page is accessed, the nextcloud will autologin using the router's login credential.
When the nextcloud account database does not have an account that has the same credential as router credential, a failed login will be recorded by nextcloud.
Too many of these failed login attempt will make nextcloud block the page access from that particular IP address.
When you created a nextcloud login credential same as the router login credential, whenever you access nextcloud, that particular account will be logged in automatically.
This behavior made login to other user account impossible.