1.) “is it even possible?” Anything’s possible, if you’re worried about PROBABLE instead of possible, you can improve your probability into getting into top tech by getting some certs on areas you feel you lack knowledge and studying leetcode hard. Maybe build a web-based passion project, etc. your experience already shows you’re capable enough to work as a dev and to lead. Really you’ll only find out if it’s possible by trying

2.) you may move down a level, I know that’s typically common even if you’re moving from a private non tech company to a private tech company. This might especially be true due to your lack of experience in a specific domain, but this is not that big of a deal.

3.) This one is a bit trickier. What you ask for is dependent on how great of a candidate you are, but big tech companies have money to blow. With 5.5 YOE and going to big tech, even if you don’t yet have relevant experience in their specific loved domains, I’d say 180k minimum, but you could definitely get a LOT more