Brave however is riddled with Crypto and AI crap. It doesn't have any useable support for multiple profiles, too: last time I tried it, it would end up showing various errors on every startup and you couldn't have two profiles in the same window.
I just start Librewolf with -P and keep profiles in separate windows. Easy, already fully supported, and allows things like different themes to highlight the fact I am using different profiles.
I've been running it for years; I see none of what you mention. I turned off a couple of settings (literally took <5 minutes) and I don't see anything crypto or AI related anymore.
Same. I’ve been using it exclusively on macOS and iOS for a few years now. When you first open it they do show you all those features but as ochronous said you can completely disable them. If they forced crypto and AI on me I’d be out in a flash.