I am using Fedora Workstation 36. I am using linux for over 5 year. I never have to concern about user management.
Now i have to share my computer with other one. So I have created a user account for her, but don’t given administrator access, she don’t need it.
I want to control both account from my account. I want to install, show/hide application in that other user account from my account , want to control GNOME extensions if needed.
And, she shouldn’t use installed applications by mine(or my account).
In short, you cannot prevent another user from using apps that are installed system-wide.
You can limit them installing additional apps, or using apps that are installed at a user level, and they would have no access to data/files/apps that are installed in your home directory tree with the default permissions, just as you would have no access to their home directory without using superuser permissions.
Since you did not give the other user admin rights they are very limited in what they can do and one thing for sure is they cannot make system changes. Their rights are limited by the linux system permissions as well as by selinux restrictions.