This is why I'm hopeful that at least one of Ladybird, Flow, and Servo emerge as a viable alternative to the current crop.
The Flow people are talking about when they talk about Ladybird and Servo is https://www.ekioh.com/flow-browser/ which does have it's own engine. It has a similar level of standards compliance to Servo and Ladybird, although it's not open source which puts it in a somewhat different category.