I would absolutely pay for the development of an independent, open source, privacy oriented and user friendly browser. I would never pay for the shitshow the Mozilla Corporation is.
I would find $5-$10 per month perfectly acceptable.
For now maybe donating to Ladybird [1] and Servo [2] makes more sense?
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[1] https://ladybird.org/ [2] https://servo.org/sponsorship/