I used Floorp and Firedragon (formerly based on Librewolf, now on Floorp), don’t know if they are cutting out the AI cruft. They have other privacy features, mainly their choice of default settings.

I’m currently using Zen, which made a statement:

We noticed a rising interest regarding the use of AI in browsers. To be clear about our position on this: Zen currently is disabling all AI features included in Firefox and will continue to do so.

https://ohai.social/@zenbrowser@floss.social/115731119727477276