You're confusing the browser and ths search engine, I think. I use various combinations of Firefox and Brave browsers with Qwant, Brave Search and Google Search on different machines and AFAIK, I've only seen the crypto stuff in the Brave browser when I initially installed it. Quickly went through settings to disable that stuff and never seen it since. Still the best Chromium browser, and good to have next to Firefox in case of compatibility issues. Privacyguides.org is clear about that.

The search engine seems decent too, I haven't noticed a big difference between Brave Search and Qwant so far, they are both fine, and less heavily manipulated than Google