macOS Big Sur - gatekeeper? slowing down opening applications
You absolutely want to open up all outbound ports to the entire 17.0.0.0/8 address block which is assigned to Apple as a first step.
Next, get this article to your network and security teams.

https://support.apple.com/en-us/HT210060

If they balk, call your Apple store (or whomever you buy you Macs) and ask for a short call with Apple Business to sort out why doing all of the things is the best plan for speed and security.
If your team isn’t convinced this is correct, set up a new network segment and do some A / B testing. Apple has made some very nice optimizations so notarization, certificate validation and other checks are cached very well now. Some even work with a proxy but some will not tolerate any manner of proxy or deep inspection / manipulation of the traffic.