It seems I will only have space for one or two of these in my Venice itinerary. If you had to cut one--or two--which would it be? I would want to prioritize the most unique places, places most unlike what I'll encounter in Florence or Rome for art galleries or palazzos.

I'm not sure I can meaningfully answer the question, but as I understand it, the Accademia -- which I adored! -- would likely be more similar to other art museums you would likely see elsewhere in the world. It would also, I think, take much longer to visit than the other places you mention ... but maybe that's just me.

Good luck with your choice!

The Scuola Grande is definitely worth a visit, especially if you're interested in the "3 Ts" -- Tintoretto, Titian and Tiepolo. It's been several years, but I think we spent more than half a day there. (Admittedly, we're slow museum visitors.)

But if you want something unique and most unlike what you'll see in Florence or Rome, go to the Peggy Guggenheim Collection in her Grand Canal villa. Another would be Palazzo Fortuny which re-opened after refurbishment in 2022.

Neither. I’ll second the Peggy Guggenheim Collection. It’s unique and there isn’t one like it anywhere.