The first episode was the cross-over with Abbott Elementary. I did watch the other part of the cross-over as part of Abbott Elementary’s season a few months ago.
It was kind of painful to watch - the Abbott Elementary parts. The mockumentary comedy format is terrible. So you end up with the mix of normal It’s Always Sunny in Philadelphia humour, then occasional interviews with the Abbott Elementary cast. Apparently, the only joke in the mockumentary format is to keep staring directly at the camera.