This is the correct answer. Having your users run multiple browsers by default (instead of with whitelisted exceptions) is now multiple attack surfaces the org has to manage.
Very curious how you avoid supporting multiple browsers. Apple, Google, and Microsoft each require users on their platforms to use their native browsers for secure connections.
And if your company has any web presence or apps, you usually can't cherry pick which browsers your customers can use. That means some portion of your company will need access to other browsers for QA purposes.
At the minimum I might say you only allow Chrome to access Google Workspace/SSO, which is needed to access like 95% of company resources. This is, in fact, the topic of the OP.
You can do additional device management to lock down the rest of the machine. You can force Chrome and restrict Safari/Firefox/etc on Mac just fine. Same for Windows.
