You need to think about what you mean by stock Android. If you mean a phone that had Google on it but you got rid of the Google parts such as GMS then that’s not really stock and won’t increase your privacy.
As you know there are more privacy friendly distributions based either on AOSP or Linux. But you will not be able to use apps that rely on Google services.
So the decision will come down to what you use the phone for.
Good question, I was thinking about this the other day. The reason being that development of several fediverse apps has seemingly stalled because the previously active developers have life issues. (I’m not moaning about it, just a straightforward account)
It seems to me that FOSS developers wouldn’t want their projects to be popular. Because that comes with pressure to constantly improve or expand and it takes up more time. So they start a Patreon or similar but that adds more pressure.
When projects are community developed then I see disagreements and personality clashes which increases stress for lead developers.