Congratulations, you have gone from newbie to beginner in world of Blitz3D development. Most of your issues have been "Par for the course" for Windows developers for 27 years now.
I did modify graphics command to plain 1920,1080 and found simple close window on desktop windows icons after 3 fisted salute worked ok. but doing so found issue with RuntimeError command so will get back to you.
Not zarch but 4 a good compatibility test, this is another Stevie G game in similar style that may scratch your itch.