only Groupware function (mail, calendar, talk and video) needed

hello all

i am using Nextcloud in my small business but it still runs as kind of POC.

i reduced all apps which are not used. some of the functions i cant remove for example “Files” im top left menu, Appearance and accessible, Help, apps, Some fields of the Profile, etc

the user should ONLY have access to emails, calendar, talk, video, tasks, contacts.
everything else needs to be removed.

can anybody point in the right direction how to remove

  1. “Files” im menu
    2, appeaance in user menu
  2. help im user menu
  3. apps im user menu
  4. a couple of fields in user profile (perfect would be if could be synced with infos from active directory)
  5. all access to locally files and folders (on the next cloud server)

we only need groupware function and its our requirement that everything else will be disables or removed.
thx for your input

The only possibility I know is to work with user groups and to include them in the APP section in the right menu:

But this function works not properly.