You don't mention "which" browser, but....
Generally speaking, in most instances, a Windows Update OR in this case a Windows Upgrade does not impact non-native Windows System files to include third party browsers or for that matter most third party software.
BUT
It's up to any third party software manufacturer to assure and affirm that their particular product is Windows 11 "compatible"
We've all heard numerous complaints in the past "My insert name of software here" doesn't work after a particular update or upgrade.