Hey,
I got my BG 3 Standard on GOG about 3 months ago. ~2 weeks ago I got BG 3 Deluxe on XBox. I have enabled cross save on both and signed into Larian on both (I see both of them linked on Laraian's page). This resulted in my campaign from PC to become available to XBox and playable there.
Recently I have started new campaign on XBox and unfortunately I can't get those saves to be visible / available on PC :/ and I'm not sure what to do to fix this. When I save on XBox I see "saving" message and then followed by "saving to cloud" (or something like that).

I wanted to be able to play this game on both platforms and benefit from Deluxe Edition content. Moreover, I would like to continue my XBox game as I have already put some hours into it :)

Can you advice me what shall I do to make those XBox saves visible on Windows GOG version of BG ?

Are both your Xbox version and PC version of the game updated to same version?

Some people on the forum was having trouble getting cross-save working on older versions of the game.
I don't know if it was fixed or not. I don't use cross-save.

edit: https://www.gog.com/forum/baldurs_gate_3/missing_cross_platform_save_option

cross save doesn't currently work on Gog... a fact both gog and Larian are very aware of

I have seen that there were issues with older versions, but in both places I have v4.1.1.4251417. And I have seen and enabled proper option related to cross-save.

I have seen the linked thread and probably ti suggest that it works for some other folks? Not sure what might be the issue in my case...

From my understanding there is no difference with the Xbox version and the PC version, maybe just processing and GPU power and the physical goodies with the boxed version.

So you are playing the same game on a different platform.

I saw this thread on the Larian forums and its not looking too good for the Xbox version, some sort of save bug/deleting saves. I would just continue playing on PC instead until they fix the bug. (microsoft? Larian? idk)

https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=927734#Post927734

edit: also, apparently on Xbox, when you make clips of your gameplay, it automatically uploads it into the cloud and shares it to the public. THIS is the DEFAULT setting. People who are clipping BG3 gameplay are getting BANNED on xbox. Make sure you turn that setting OFF if you are clipping any sexy times!!

just to update Microsoft refund doesn't work on media by default however Microsoft have come out and said they will honor refunds of BG3... they can afford it

cross saves don't currently work on Gog and thats since the PS patch came out... Larian decided to remove the option to tick 'cross saves' from the ui but that just confussed more people so they put the tick box back

yes there is a tick box again, yes it says syncing and wait while we do this but its just a small issue of no save file gets synced

yes Larian is aware, yes the issue is at their server end so there is little can be done about it and while we can copy/ paste files as a work around on PC that doesn't help Xbox users

Yea, Larian posted on Former Twitter, that MS issued a firmware update to fix the save bug on Xbox.
Here is the discussion on Reddit..

https://www.reddit.com/r/BaldursGate3/comments/192klvq/larian_update_via_x/

edit: Also with the recent Hotfix #16, modded saves on PC will no longer sync with console.