The moat isn't caused by a lack of non-chrome browser engines, it's because so few people use a non-chrome browser engine. Firefox already exists - it's just that ~no-one uses it and for websites that don't work with it those users have learnt to just open up chrome.
I'd love for the moat to be broken, and contributing to a browser engine like ladybird would be fun - but it doesn't contribute to breaking the moat. I'd love to know what would.
If anyone's looking for a reason to try a switch again, consider this your sign.
On chrome-based browsers the same pages on the same computers on the same network would load in within the blink of an eye, with no pause.
I eventually gave up and went back to chrome after Firefox being my daily for years. I prefer the dev tools in chrome anyway TBH