It's really the worst time of the year for something like this. I hardly remember a time when I wasn't completely swamped with tasks before Christmas. A summer puzzle would be much more doable...
The puzzles are up year round. You can go back and do prior year puzzles any time. There just won't be any of the community from doing it during the event.
The real problem for me is that once the last few days of the puzzle roll around, I'm too busy running around to different Christmas events to have time to squeeze them in.
I completed it in 2020 and felt extremely accomplished. I doubt I'll get through all of them this year before losing interest, got too many other projects going, but I always have fun with them.