I only use the Files service (not calendar or any other) but when I go to Settings-> Administration-> System it shows me the UTC time (my correct time is UTC + 1)
Is there a way to add a variable in the config.php file to tell me the correct time zone?
On the server, the time is correct.
Sorry, it was my fault, the time was wrong on the server, checking it with the command: “date”.
Regarding what you have sent me, I really like it and I find it very interesting, now I know how to force the language and time settings on users.
I am no expert on this piece of software so wait for others to reply. I am sharing my experience about the same issue on my self hosted NextCloud (snap) Home Server.
The easy way I see,
Log into your web interface (every user may to do it by themselves)
Under Personal Info, user may set their own locale
That updates the system info in admin page (if that user has access to admin) too