I tried to use it for years as my "personal" browser while Chrome was for work. It would regularly cause the system as a whole to be slow when video (Twitch/Netflix) was playing. Switched to Vivaldi for personal and everything works smoothly so far.
I don't know much about either one of them except that Brave is (fully?) open source while Vivaldi is not.
I get that Chrome could do all of these alone with profiles but I prefer having the UX of separate applications for each.
What would that accomplish?
What would what accomplished? Moving off of Chrome to a different Chromium based browser?
Presumably I would retain all the high quality that I enjoy from Chrome while avoiding Googles spyware services. Edge, Brave and others remove them. In the case of Brave I believe I would also get some decent adblocking without having to worry about what Googles eventual Manifest v3 enforcement will do to uBlock Origin.
4K videos in mkv/H.264 format i can play fine though.
The issue here is the hardware decoders capability;
Depending on which browser you use, and whether your Macbook is connected to power, websites will send you a different video/codec/size.
Here's a random post that sort of describes this: https://apple.stackexchange.com/a/409764