TIL they’re called plantation blinds! The slats swivel open and closed as opposed to the entire thing raising and lowering but I assume that’s what you meant. No external rod or handle, all of the slats are linked inside the frame somehow.
Edit: Actually knowing what they are has helped my search massively. Looks like there’s options on Aliexpress, albeit not particularly cheap. Thanks!
Nah that one attaches to the twisty rod thing that you get on normal blinds. I need something more like this but I can’t find a non-Aliexpress version. Not that it matters cos I’d need 5 of them and that puts the idea out of my price range for the foreseeable future.