First off, for singleplayer/local co-op better use installer labeled as 220.127.116.11. Maybe some newer. Two latest offline build from GOG do not patched to 1.1 (only exe file are 1.1). 18.104.22.168 latest be available labeled as Windows XP compatible version.
I'm not sure about Galaxy online build, cause yeah - Steam. I use GOG only as offline DRM-free store.
Although I never have problems with any Steam/GOG/retail builds on my Windows up to 8.
Check more section - must be option to customize launch.
Buckup original exe and replace with new one.
GOG not related to mods. Maybe support can help with problem itself...
Some program interrupt windows.
Or check Compatibility section of exe Properties. Check off any checkboxes there. If not help - try to enable(back) Fullscreen optimisation, DPI scaling wrapping...
Ofc run as admin even from X:/Games/. For game exe or for Galaxy exe if you start game using Galaxy client (must be installed to X:/Games/GOG).
Windows can wrap own scaling size. Do not set higher than 125% - Windows never do it good, no soft support this as well, and even 1w5% can lead to a some problems with windows.
Turn off/default/by application any option in AMD CCC tool except maybe Vsync.
Main menu for Battlefront 2 as I remember - 640x480.
PcGamingWiki can provide more info - but this is Wiki, read carefully and sceptical, especially for sections about unofficial patches/mods fixes
Post edited November 29, 2020 by QWEEDDYZ