Fork Firefox, bundle uBlock Origin, Sponsor Block et el and sell it is a consumer web security product (that's not complete shit) with a monthly subscription. Use some of the proceeds to support the devs working on the underlying tech, similar to what Valve are doing for Wine, Proton and Fex.
Bonus points:
1. Multi layered approach to dealing with ads and other malware.
2. A committment to no AI or other bloat - that's not what I'm paying you for.
But I'm not pitching a browser. This is a web security product which people do pay for - it's a billion dollar product category in fact. The only functional difference is that the malware and fraud protection it provides is demonstrably superior to all of its competitors.
I think that's false, with the current state of internet, advertising everywhere, enshitification and monetization of users private data, some people are ready to pay for services that were considered "free".
I am paying for kagi, and I would pay for a good, private browser (I know they make onion but I'm on linux, not macos or windows).
Vivaldi is a decent option if you aren't specifically looking to get off Blink as the engine. It has an integrated adblocker and many other privacy-related features.
Bonus points:
1. Multi layered approach to dealing with ads and other malware.
2. A committment to no AI or other bloat - that's not what I'm paying you for.
3. Syncable profiles.