Disable installing software with exe and msi

I have a Windows 10 PC (pro) and it's a shared PC at home. I have only 1 account on it and it's shared with the family.

The main user is at administrator level and is only the main account we use.

I could setup 3 accounts: 2 as a standard user and keep 1 as the administrator but I dont really want to as this PC is only used for Office by everyone as we are all adults. The PC doesn't even have Internet access unless we plug the cable in.

Now my question is because the main account is at administrator level, they can install software that comes in either exe or msi format.

Is it possible to prevent the installation of software so that only 1 person can install software just by a click of a setting or registry change so that no one else can?

I have tested with GPO by disabling Windows Installer Service, but that just stops msi files from running. It doesn't stop exe setup files from running.

What I would like is to run either a batch or powershell script that I can run and it stops the installation of setup files from loading. If someone wanted some software installing I could double click this file and install the software and once complete, click another file that prohibits other software from being installed when I have finished using the PC.

Any ideas would be grateful?

It's safer and easier to just use Windows Accounts, as it was designed, and just create Standard privilege Local Accounts and password your Admin acct; imho

I did start doing that but it got annoying having to log off and then log onto the admin account, make changes, install software etc then log back on. I thought there would be a way to have an admin level account but block installation of software installation. Simple switch in the registry or service that can be run from a hidden file (without anyone knowing) that can enable/disable installation.