Admin account on user privileges

Dear team,
I am admin user and would like to disable the possibility of changing configuration of that user.
Also for that user I would like to alter the email that is confirming the activation of this user (removing the ‘sharing’ and ‘download app’ link).
Can you pls tell me how I can do such? Thanks for letting us use this great solution.

Nope. Admin is admin, not a less privilege admin or a more privileged user.

Better have a non-use full right admin, and a regular account for dayly operation. But you can elevate this user to be the group admin

Can someone tell me if there is an app to config file access security and welcome message layout?
No such parameters available (perhaps I overlook something).

hello again,

files access security ?? i don’t clearly understand what you want.

NC work like this:
User1 get files1
User2 get files2
User3 get files3
User1 cant get file2
unless
User2 share file2 with user1, user1 get files2, not User3.

NC is build around that.

For message layout, there is app theme
https://docs.nextcloud.com/server/stable/admin_manual/configuration_server/theming.html
and
https://portal.nextcloud.com/category/branding/8/

I would like to add kind of guest account to a user status, in which he/she cannot upload files but only download (remove from menu) and configure the welcome message for this kind of user group to exclude the app install link (remove from welcome message).

Will check your suggestions, thanks for that.