Thanks for the reply. I’m going to try subdecks and see if Anki chokes, for now. It’s much more convenient, so long as I don’t choose specifically the sub-decks to study, which would be cheating.
The Anki manual is very badly written. Anki still tells me I have “a lot of decks”, even though it allows sub-decks and doesn’t specify how many is too many. Is best practice still to browse and move cards into a single deck for each category?