All POSIX compatible shells have their quirks and differences because the common POSIX part is rather small, so you will need to learn them anyway when switching from one to another. Fish is not that different from them (to much less extent than something like nushell) and it benefits from having less ancient baggage.
There is also Ladybird browser that IIRC already has a more complete web standards implementation than Servo despite being a much younger project. Though it’s still far from being ready and performance is really bad. But so far it seems that it’s going to outpace Servo.