I only have one comment that I have already made and it got some traction so worth bringing up again. The comment is that there is value in separating e2e/integration tests that are not version specific from component/unit tests that are. There should be much less churn in the non-version specific tests therefore reducing the overhead of having a separate repo. On the other hand, changes to version specific tests normally are made at the same time as their respective code changes. I am not sure if we know which tests are version specific or not and if we are ready to make a forward looking decisions like this now, but I think keeping the test repo but only having non-versions specific tests there would solve the problems that have been presented. I think it also might solve the problem that Gabriela's proposal would solve, although I don't fully understand that problem.
Anyway, just wanted to bring that up again. One single repo or two separate repos will both work. Just a matter of the tradeoffs.