In my workplace we use Webex and MS-Teams. For MS-Teams, starting with Big Sur, my employer sent instructions for MS-Teams. The instructions say that Safari no longer works for MS-Teams and instead to use Chrome. One copies the link for the MS-Teams meeting and pastes it into the Chrome browser location. Then the needed pop ups occur and one can join the meeting either using the MS-Teams app or in the Chrome browser itself.
I have tried a variety of ways to get around this but none worked. It's an incompatibility. So now we all use the copy/paste method above and use Chrome (or Firefox, which also works, but my employer recommends Chrome for MS-Teams).
If there was a simple "fix" for this we would have found it. We have thousands of Macs in use here.