Almost all "alternative" browsers are Chromium based or Gecko/Firefox based. If there are any that are truly scratch-built other than the text-based browsers such as lynx or w3m I'd be interested to hear about them. I'd guess they are extremely limited in features.

The graphical alternatives that I am aware of are extremely limited, such as NetSurf.

You are looking for "ladybird"

Not the commenter you're replying to, but I've been using LibreWolf for the last few months.

It's a bit more privacy focused, so may need some tweaking to your liking (by default it won't persist history, zoom levels, cookies, etc.)

LibreWolf, Iron Fox, and Brave are all worth a look, I think.