For some reason, none of my games bought purchased and downloaded from GOG are launching, using MacOS Catalina, despite them not having the marking that 32-Bit apps generally have (with the line over them). There's no error message or anything, they just bounce in the dock, settle for a second, and then close. I've tried launching from GOG Galaxy as well as applications.

Examples are: Book of Unwritten Tales; Grim Fandango Remastered; Expeditions: Conquistador; Icewind Dale EE;

Has this happened to anybody else, and if so, does anybody have a solution?

Thanks

Latest versions of Mac OS are 64bit and don’t run older 32bit games. Clearly states this on the game page for grim fandango remastered (at least), see the not further down the page. Also, works on does not show Mac OS.

Your first example:
https://www.gog.com/game/the_book_of_unwritten_tales
"Mac notice: The game is 32-bit only and will not work on macOS 10.15 and up."

edit: I looked up the other games and they all have the same disclaimer, except for Icewind Dale: Enhanced Edition (so I don't know what's the issue with that one).