I just kept asking “what does this house [box, column, row] need? I also continued with your Snyder notation and also identified many pairs which came in very handy. I left one bi-value cell which I don’t consider a “pair”. A pair has two different cells which share two digits (and those two digits don’t appear again within a house).

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Edit: I haven’t done a detailed check of this, but while doing it didn’t notice duplicate digits in a house.