> But what steps have OP taken to start decentralizing to mitigate those risks?

You don't know they haven't already starting thinking/implementing ways to address those risks. And... it may also be that there's not enough political power to make changes substantive enough to address the systemic risk. OP mentioned 300+ developers on a team - that's a large place. There may simply not be the ability to wield enough influence to make real change to reduce this sort of risk across the board.

Documenting your own stuff, coming up with some better ways to share knowledge, pairing, etc - that can help reduce some localized risk, but you don't know that they've not done this.

You’re correct, I don’t know they haven’t tried to mitigate the risks.

But post also points to being lonely of sorts and a sense of dispair. As your last paragraph describes, if OP pair programs, does some mentoring, etc, why would they feel lonely and post on the internet instead of chatting it through with the people at the company?

If so many people are coming to him/her for things, they def have some implicit power. Not knowing how to constructively use that power also lead to my support of the “don’t be a manager” post (yet). If OP figures out how to scale themself out, then by all means…

I have no idea if I’d be a good manager. But I don’t think this is a fair connection to make. I’m currently in a similar situation of being the built it all does it all go to designer programmer. And I have desperately tried multiple ways to make this not be the case. But if the company doesn’t support your efforts to do so, does it prove I’d make a bad manager, or that that company I work for has some shortcomings?