As mentioned, it is helpful to go to the front desk at the first resort and have then check you out as I have not always done that...do split stays a lot of my trips...and I never get the room ready text at my 2nd resort,
When luggage transfers, it usually won’t be there before 3 to 4 pm. So, if you want to do pool time waiting for the 2nd room, be sure to leave that out.
Because you could be homeless between the stays, we always make it our Disney Springs day. We stay out late the night before, sleep in, check out at 11, bring Our things to bell services, and then head to DS to eat lunch and shop. By the time we finish and head back to resort #2 it’s pretty close to 4 pm and our room is usually ready.