It's also very possible that you'd be happier and more effective on a different team at the same company. All of these companies are big enough to have a great diversity of systems, from nascent projects to polished but boring workhorses, to unmaintained balls of tech debt that they can't turn off but nobody wants to work in. Often if you want to influence the direction of a codebase, it's best to get in on a new project or system that's just being built.