As a retro PC gamer, I've started to dread seeing that "GOG Preservation Program" badge on a game's store page. They call it "preservation" but it's actually the opposite. If anything, a more appropriate name would be "modernization" since those changes were made to allow the game to run more smoothly on a modern Windows OS. Sadly, GOG doesn't seem to offer older (retro friendly) versions of their offline installers for download.
So nowadays, when I'm buying a game from them, I first check if it has that badge, and if not, I look at the system requirements to see if they list anything below Win10. While in the past, GOG would ship games with some wrapper files that were relatively easy to remove if you wanted to use your actual hardware, now they seem to recompile some games entirely, making it impossible to run them on a retro OS.
On one hand, I understand that their target audience largely consists of people who are using modern Windows, and who just want these old titles to run without too much fuss. Retro gamers playing on real hardware are definitively in the minority, and it's unlikely that we will be given even a second thought. Moral of the story: backup your offline installers before they get updated, or your favorite games will become incompatible with older operating systems.