I am having the same issue (cannot log in, and the "please wait"message shows for a very brief time) with the Larian launcher when starting the game from GOG.
I already verified the installation files and reset the launcher data.
This happened after installing the game on a different PC, and starting the game for the first time.
For reference, I do not have any Mac or PS5 save files to link to, though I do have the PSN account connected to my Larian account.