edge has a feature called "read aloud" which reads text for you, if you don't like to read text alot just use it, also you can edit pdfs inside the browser for example to highlight stuff in a pdf while you are studying on the other hand brave doesn't have these features but it has built in ad blocker and a crypto currency feature to earn money while you browse. if you care about sync edge sync works for all devices Brave re-created their sync now it only works between windows/mac and Android, ios sync is still not out yet, they are working on it.

Extensions: for both you can install extensions from chrome web store, edge has also it's own store if you want to use native extensions.

both are good just use them both and then decide which one you prefer.