I found it helpful to half-plan so there is some sort of structure. One time I didn't, and it felt like a wasting away in a fluffy bed and TV. I also get a little nuts when it feels there is only one way to do it 'right' regardless of wallet size. There are so many ways to have a good time and it depends on family dynamics, time, and the money. I don't worry about specifics on where we eat other than a general area or time, e.g. We are going to eat lunch around noon and it can be on the way out of the park or Citywalk. The one mandate I have is that everyone must rest for two hours with no electronics. I don't care if you stare at the ceiling, it's quiet rest time. One time someone chose to not mind it and that husband was a poopy pants in the afternoon. Siesta means that if someone got up too early, they do get a nap instead of powering through all day.
So that I'm not the only one planning/choosing, I try to get them involved in selecting a couple places for meals the next day (on a rotation through the family), they have their faces in phones, might as well be on the app looking at dining

They can choose if it is a must-do or here are a few places to eat depending on where we are when hungry. If you have family that getting up early is paying the iron price all day, maybe you can all agree to do early the first morning in the hotel? Then if you are staying longer, they may see the wisdom? Splitting up for early folks and sleepyheads might work and a meeting at X time at Y place? Splitting up might also bridge the 'we saw it all' and 'I missed it all' sentiments.
I see you are staying at RPR, that is going to make things so much easier with the express pass. I also like the location that it is pretty walkable if the boats are not running (we go in August which often has lightning). I wake up every day with hip pain (surgery 10 years ago went from excruciating to livable). RPR is the only bed I've slept on where I did not wake up in pain. Other onsite hotels were not as magical, so I know it wasn't the walking that cured it. I hope it is as soothing for your knees. I do bring a heating pad and big ziploc bags for ice.
For food, we ate oatmeal packets in the room so that we could maximize getting ready time with eating. I pack nuts and other snacks so that we can get get to lunch without whining (from the adults, no less!). Then lunch as I mentioned above. If it is super hot, inside for the AC (not sure how possible this is in a COVID world). Mythos, Burger Digs, Leaky Cauldron and Three Broomsticks have met these needs in the past. I like that at the HP places I can order sides to make a meal. Our family has also really enjoyed Breadbox. I hate sandwiches at home, but dang they are special at Breadbox (and it is cool and the bathroom clean). Moes / BK is also good for quick lunch if you have people in your party who want something different, but you want to eat together (and on a budget). Red Oven pizza's is also a hit as two can easily share and it's nice people watching. My one big thought on food at Universal is : why can't they make a decent chicken sandwich? Why are most of them with just mayo? Would it kill them to have some other flavor, yellow mustard packets don't cut it, I digress... Anyway, just know your budget & let others help take on some planning. Otherwise, let them know "I don't know" means Bethany's choice and no belly-aching allowed.