It’s disingenuous to act like this is some huge burden.

Having to double your software engineers, UI/UX designers, QA engineers, DevOps, and localization/accessibility specialists to handle a second browser is a HUGE burden for a non-profit.

If you don't care about quality, security, or user experience, sure you can just pass a "does it compile" test and push to prod. You'll quickly find that nobody wants to use this under resourced browser.

Or if it’s such a pain, you don’t bother and just ship the WebKit version everywhere.

This is exactly what Apple wants. They don't want to give people a real choice because they're scared of real competition.