Proxy Authentication Requests - turn off any attempts to connect to the internet

I have some users who have absolutely no internet connection.  Despite in the past having put in various paths to allow through proxy, we still constantly get proxy request pop ups.

Because of this as a group of about 400 UK users we are considering stopping using adobe products as it causes major issues.  It doesn't seem to work with client side proxy no matter what you try.  Adobe is the preferred PDF reader but if it continues with these issues we have no choice.

Can you turn off any requests within Adobe DC to even attempt to get to the internet.  I can manually manage updates and would much rather do this anyway.

It's been a frustration for our users for the last 3 years now.

Thanks in advance for any useful advice.