It may seem bizarre, but using multiple browsers has a purpose
For example, Firefox is the only browser supported by the online access systems of the courts, basically I need this to be able to work (I'm a lawyer); as for Google Chrome I use it logged in with my Google account to use the services of this company like Gmail, Youtube, Youtube Music and so on.
As for Brave it is my main browser and Edge, well it has an excellent PDF reader and a very pleasant reading mode, it is a very good secondary browser and could easily replace Brave (which maybe it will).
In addition, using different browsers for different uses is a way of trying to maintain an anonymous identity on the internet.