I suppose this comment will not be liked very much, but let me offer one another perspective on this. In one team in our organization, someone was hired who offered themselves (by their own initiative) as a developer coach with the intent on pairing, reviewing and in general helping other devs. They were very confident, and as we employ team recruiting, the team decided it's worth a shot, as the candidate displayed knowledge of relevant skills and - as already mentioned - was very confident to educate his peers. It was an intra-organization lateral move, so not much risk involved. Everyone was on board with that decision, and the expectations were clear: they would not be expected to produce code and/or design documents and so on, they should just support the other devs. It should be mentioned that the team they wanted to join was a really high performing team - still (or because of this?) they were open to the idea of having a well-trained, experienced pairing partner and so on.
Well after a few weeks it turned out not so positive. They had quite a broad knowledge of things, but not in depth. They didn't think far enough (like for example, giving the tip to "use a FIFO SQS queue" despite not really understanding the fine-print, but still they persisted and it ended up in a prod rollback), they preferred educating about code style, didn't really listen to feedback (not in the sense of ignoring it, they didn't even realize that they weren't so senior compared to the rest of the team at all) and in general slowed everyone down without bringing much benefit to the table.
In the end they didn't get fired or something like this. They did another lateral move as the team explained why the team doesn't want to continue this. After their next team change, they talked about that this specific team didn't want to accept their help and that they had received bad feedback since they didn't produce code.
Obviously this is just an anecdotal counterexample, but still this can happen as well.