Is it possible to "freeze" a deck to the specific printings it has? Alternatively, is there a way to know which cards in a deck are not pinned to a specific printing? Thanks!

Yes, I also think the following features would be useful:
- Filter based on presence/count in built decks
- Filter based on presence/count in tradelist
- NEW: Export count in built decks as an extra (optional) column in CSV
- (The count in tradelist column is already present)

I've actually submitted a "Support & Feedback" about this before seeing your post. That's good to know I'm not alone.

I have those LTR 2023 promo cards, I'm not sure how to classify them. The only edition I see is The Lord of the Rings: Tales of Middle-Earth. I don't see a Promo Pack version, or some 2023 Anniversary Promo version. Is this going to be added? I also don't see it on tcgplayer and scryfall.

https://i.ibb.co/607hPK4/PXL-20230623-230228899.jpg