The smaller one appears to be PS4, and the larger PS5 (I got the all-digital Jackie Robinson edition). It's worth noting that I did play the tech test and in fact still have it installed, but this appears to be completely separate as it is starting both of these from scratch.
I don't expect to be able to play either of these when they finish, but regardless this is still REALLY early for a preload. I didn't expect a week ahead of time.
Edit: I also now have two MLB '21 icons on my home screen - one says PS4 and the other doesn't give a platform, but is pretty obviously PS5. I can also launch the tech test from there under Game Version if I press Options on it (and it does say PS5 on that pop-up box).

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