Your boss told you exactly what you need to do: take more ownership :)
You already mentioned you own one part of the codebase, why not expand on that and find another (hopefully critical) part of the codebase and become an expert/owner on that piece too?
Also, it's not all about writing code. Your boss wants to see you put the needs of the team above your own, so look for opportunities in which you can increase team productivity, reduce risk, and help grow your team in terms of headcount and knowledge.
Also, try not to compare yourself to others, although I know it's easier said than done. Figure out what your goals are and do everything you need to in order to achieve them. Who cares how quickly others progress? Focus on yourself and your own success.
Hmm, maybe I suck at communication in the context of team discourse? I've never really had a great example or explanation of "ownership" outside of a bizarre corporate lingo form at Amazon. I guess I'm curious as to what "value" is in distinct terms, I still feel pretty lost here?
You realise that the bizarre corporate lingo is part of the management skillset right?
Taking more ownership, means your boss wants you to make decisions and lead the direction. Not like a dictator, but by example.
Value is meeting your requirements the fastest, least conflict ridden and safest way possible. Sometimes that’s clean code, other times that’s happy employees and other times it’s getting a finished product out the door regardless of the amount of spaghetti. Often it’ll be a combination of them all, with getting stuff done being the most important in almost every industry. The exception being places where safety matters more, like when you build airplanes, and even there, you only need to look to boring to see what “value” often means in management.
You already mentioned you own one part of the codebase, why not expand on that and find another (hopefully critical) part of the codebase and become an expert/owner on that piece too?
Also, it's not all about writing code. Your boss wants to see you put the needs of the team above your own, so look for opportunities in which you can increase team productivity, reduce risk, and help grow your team in terms of headcount and knowledge.
Also, try not to compare yourself to others, although I know it's easier said than done. Figure out what your goals are and do everything you need to in order to achieve them. Who cares how quickly others progress? Focus on yourself and your own success.