are you looking to do this with young kids? not sure if you can sit at counter serve tables without ordering food with reduced seating. might be some tables in mask relax stations but not sure. know my young grandkids would not do well sitting on a bench to eat without a table
You are allowed to eat outside food at any table and chair areas in the park. We are budget minded and also have allergies so are used to doing this whenever we travel and it works fine at Disney too. We were there March 13-15, and ate our picnic at quick service table areas at Hollywood Studios Sunset Blvd, The Land at Epcot, and across from Pirates of Caribean at Magic Kingdom (wish we'd gone to terrace near tomorrowland, forgot it's my favorite). It was crowded and we had to hover for a table, but not long, not different than anyone else or any other time.
We carried a backpack cooler of food and a water bottle backpack for our family of 5. We planned to get a locker, but never did, was no problem having the pack on the rides and we were not bothered carrying it.
We bring sandwich bread in boxes so it does not get smashed, put ice from the hotel in plastic bags for cool packs, and put packages of meat n cheese at bottom or pack. We assemble sandwiches at the table using knives from the park. We brought:
Hummus n carrots n crackers
crackers, cream cheese, smoked salmon
Apples n cheese
peanut butter n honey sandwich
ham and cheese (mayo n mustard packs from park)
My husband is on a special diet so brought his cooked white sweet potatoes and roasted meat and guacamole
Pringles (pack well, special junk food) , small bags of snacks like crackers, bars, chips
Buy things in containers that pack well. I shopped at Aldis and they have small containers of hummus and guac and hard sided pre sliced cheese slices and resealable meat pacs that pack well, and then seal things in gallon size ziplocks in case the ice leaks. You can get ice water from any cashier counter, or large cups of ice if you need to refresh the ice.
We do this then splurge on interesting snacks and drinks.