I think we have eaten at all of the signature restaurants. Our kids are 6, 4, and 1. We usually try to get a 5:00 reservation so it isn't crowded. We just pack things for them to do while we wait for food. Our favorite is Citricos. California Grill has gone down hill recently. It used to be my favorite but now I feel like it is "herd them in, herd them out" for $$$$$. We haven't bee to Narcoossees since it reopened. We recently got the big round table right by the kitchen in Topolinos and our kids loved being in that location. Plus, it was a little louder there. We have gotten put in the back room at Flying Fish a few times and I am always paranoid that the kids will be loud because it is very quiet back there.
In the parks, we enjoy Brown Derby the most. Tiffins has great adult food but the last few times we have been there, even though we ask for the kids food to be brought out right when it is done, their food has come out 5-10 minutes after ours. We won't go back there for a bit which is unfortunate because the food is fantastic. Le Cellier is good but I actually prefer the general table service restaurants at Epcot. My kids love Space 220.
Cell service can be a little spotty so we try to download something on Disney + to our phones as a "just in case they are being really bad". Be sure to download because it can be really slow to load with both Verizon (my phone) and ATT (DH's phone).