No cloud save for BG3 on GOG! [as of Sept 2023]
Currently, as of September 4th 2023, there are no cloud save for Baldur’s Gate 3 on GOG.
The Larian Studio cloud save has been disabled and GOG has not enabled their cloud save functionality.
Therefore, the current option is to manually copy your saves from one PC/device to another. The saves can be found here:
LOCALAPPDATA%/Larian Studios/Baldur’s Gate 3/PlayerProfiles/Public/Savegames/Story
Hopefully in the near future (maybe when the PS5 version is released) Larian will re-enable cloud saves for ALL platforms!
Other players experiencing and confirming this issue:
https://www.gog.com/forum/baldurs_gate_3/am_i_the_only_one_who_doesnt_have_cloud_saves_in_bg3
https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=875225
And of course Reddit: