Most places I've worked testing is just table stakes and built into the processes of all the teams. Getting to the higher "seniority" levels is generally just about putting together a history of impactful accomplishments to cite, and using that experience to have a wider impact on the business besides the code you write. Like when you are in a meeting you are the one suggesting better ways to solve a problem, or you get a bunch of engineering teams to go in the same direction together to solve a problem no one team could solve alone, or you solve an important problem no one asked you to solve because only you could see it was a problem. Stuff like that. Also people like working with you and you socialize your self and are aware of what's going on in the business.