I recently went to a conference so couldn’t go to the parks until after 2pm each day(and it was President’s weekend), yes it’s busy and the ride lines are longer midday but it’s still better than not being at Disney.
The RDers will be getting tired and cranky from the heat, some probably even leaving for midday nap, but you’ll be fresh and energized so do whatever works for your family.
I think you just have to tailor your strategy to avoid the biggest crowds.
-Plan your FP+ 12pm,1pm, 2pm so you’ll be guaranteed with some good rides midday, then you have potential to pick up more in the evening.
-in between those FP, plan to do COP, HOP, Tiki birds, PEopleMover, Laugh floor, Pholharmagic, Tom Sawyer island or whatever high volume/low wait rides/shows appeal to you
-eat before you arrive or plan to mobile order
-Book your FP+ for headliners, so you can hopefully pick up the easier rides as 4th, 5th, 6th later that night (ie Under the Sea, IASW, WTP)
-if fireworks aren’t important to you, that’s a great time to do rides with shorter wait times
Entering at 11 or 12 is still over 8 hours in the park, I wouldnt hesitate to go, have fun!