I am sure will be busy as it most of the time now (apart from currently!) last two weeks of august are actually now actually one of the quietest times to go, American schools go back second week of august. We plan 2022, although will have to go for the first time in August, having always been in autumn before. There there will still be a lot of people putting off travel and also the fact that many peoples finances will have taken a hit, so wouldn't think 2022 will be much busier than say 2018 and 2019. It will be likely 2023 before things start getting fully back to previous attendance levels. Plus it is rumoured Disney are now not planning to open Tron until fall 2022 (hope it opens in summer though) as they are spreading the new attractions out to have biggest impact (Guardians coaster should open in spring/summer 2022). Think i read Disney told investors that it will be at least 2023 before they see a full recovery.
Over recent years Disney and universal have done a great job at changing when people visit and attracting people on what 10 years ago was classed as quiet time. October is now generally busier than a lot of summer time, November has also got increasingly busier. The busiest times now are March & April (Spring break and Easter), End of May until start of august, October, 2nd half of November, mid Dec through to start of Jan.