You personally I believe without reservation about this, but the thing about creating a legal person is that it’s separate from you. Its control can—and in the long run, will—change hands. So please, please write this down somewhere, ideally somewhere binding on its future (can donations have conditions?).

Despite that, I hope you'll consider a "pay what you can" popup when downloading the browser, or a donation button built into the browser settings page along with a one-time reminder, or something like that. I don't think that would be monetizing your users in any negative, extractive sense like ads do, it would still essentially just be a donation, just asked for in a more obvious way and made easy and convenient to do as part of using the app, instead of a vague separate thing that'll take work to find and that won't occur to most people to do. Personally I think charging users for software (as long as it is also FOSS) is totally fine, it's probably the only sustainable model for software that isn't ads or corporate sponsorship, and it actually serves to align the incentives of the software's developers more closely with users, instead of doing anything bad, but I respect that line.

I wish you luck, more competition in the browser space is sorely needed. But please, please spend more time thinking about your finances. The surface of planet "Startups That Will Figure Out A Business Model Later" is like 99.9% graveyard. You're going to be asking people to depend on your software for an extremely important part of their lives. If you don't have a path to sustainability, you're going to do a lot of harm when you close up shop.

Between the lack of a business plan and your responses about licensing, I'm afraid I feel you're coming at this from a naive point of view. This is a seriously important line of software you're entering, please do take some time to take it seriously.

Will watch your progress and again, I genuinely love to see your project. Good luck.