Thanks for the detailed answer. I decided to follow your suggestion that the presence of SSTB in Box 20 implies that I have SSTB activities through the LP, so I said yes for each year. I then said my income was below the threshold in each year, and I'm assuming it will all work out.
I printed a PDF copy of my return, then went back and said no to the SSTB question for each year and printed a PDF of the resulting return. Comparing them showed only a minor change to the federal carryover worksheet (and no changes anywhere else), so I'm assuming that at least in my case, this is not something that is likely to make a noticable difference in my taxes in future years. (It doesn't make any difference for 2023.)
I guess this is the kind of stuff I used to pay my CPA to deal with. Unfortunately, he started making mistakes and not caring that he did, so I had to go my own way.
