Transfer ownership of project

I’m trying to transfer ownership of our project and/or (just all of it) organisation to another account (email).

Here it says it should be in Project Settings >> General Settings >> Transfer Project, but the button is simply not there:

Here it says to write to support, but doesn’t say where should I write (some form?, or email?, what address?) and also I’ve seen somewhere else, that the email support is for paid members only, so…

So I’m writing here hoping to figure it out. It’s just confusing, that all.

Thanks in advance,

More info, in case it helps:
We have organisation on sentry .io (free account). We created it under one email, then added another one, then (probably) some trial period expired. I then removed one of the emails from members in order to replace it with a managers email (thought the limit was two since I was seeing two members). But the limit for free is one member, not two, and now I have to transfer the organisation and the project to the managers email.