From what I've read, the PST support is still incomplete. The game can be roughly completed, but most of the gameplay isn't fully implemented and many stuff non critical to the main quests are not fully working.
I finally had a chance to get a copy of Baldur's Gate (Virgin interactive / White Label / 5 CDs) ! Just installed it on Debian 10 x86_64 with Wine and scp'ing the files to the Pandora as I type !
EDIT: copied the DATA, movies, Music, Override, scripts, Sounds directories plus chitin.key and dialog.tlk to appdata/gemrb/bg1, and it seems to be enough to get the game running.