We are generally weekenders but did a long-planned trip to Yellowstone/Tetons 5/21-5/29. Originally planned to stay in West Yellowstone MT, but with the west gate still closed we moved to Jackson, WY at the "last minute."
We stayed at several places over the 8 nights. All were private as the public/NFS/NPS campgrounds are still closed. As always, we chat with our neighbors when we arrive. One of the couples we met and chatted with most often was in a rental class C with 7yo twin girls. They were having a blast and the girls loved playing with our 8yo. We met them in Jackson WY and they were from Denver. We met another young family from Chicago, and another from north LA county.
Everyone we met was out and about because they were sick of COVID and wanted to get their kids out of the house. My wife and I are both medical - working at local hospitals. One couple we met on this trip were teachers. One couple was drug reps. Everyone was sick of COVID containment and were getting their kids wiggles out, including us.
I've had best luck looking at campgrounds Facebook for current status as to if they are open or not. Many of the smaller private campgrounds do not update their websites often but Facebook is usually current. It seems many/most KOA are still open and they are easy to search and reserve online.
My vote is proceed with your trip you'll love it!!
Edit: since you are basically a beginner, I would suggest you look at KOA campgrounds as they are generally open in the states you are looking at while the public CG are generally still closed. KOA also generally have hookups, stores, experienced staff, clean bathrooms with showers, etc.