How to prevent a(n old) fullscreen game from moving windows to the secondary screen?

When I play some older fullscreen games (e.g. Diablo 2 or Rollercoaster Tycoon 3), their switching the primary monitor (left one) to a lower resolution somehow causes all open and maximized windows to be moved to the secondary monitor (on the right), where the will remain even after closing the game. How can this be prevented?

I've already found some related questions but they differ:

How to move a fullscreen game to the second monitor? - I'm perfectly fine with playing on my primary monitor
Windows on secondary monitor gets moved when resolution changes - Windows on the secondary monitor stay fine
Prevent second monitor to "move" while in fullscreen games - same I guess, though an implication of the accepted answer is that the (low) resolution of the primary monitor might be to blame. I suspect the low resolution causes enough of the maximized windows to actually have their coordinates on the secondary monitor or such?
Dual Monitors Switching While Running Full-Screen Game? - that's probably a related problem which I'd like to fix later as well, but the solution might be independent

Since the games are old enough a circumvention would be running them in a VM with video scaling to my native resolution, but that's not ideal. I do however wonder if there exists a tool which can create a "virtual" kind of monitor into which the game is restricted but which is then displayed scaled up without requiring as many resources as a full VM.

windows monitor

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Quick Answer about "How to prevent a(n old) fullscreen game from moving windows to the secondary screen?"

Use the game window settings.

Use borderless windows.

Use the taskbar settings.

Utilize display extension settings.

Check for system updates.

Close applications running in the background.

Adjust the CPU priority.

Why is my game pulling up on my second monitor?

This is because of the resolution of the game. If the game resolution doesn't match the normal resolution you use outside of the game, the resolution will change and cause strange effects on the other monitors.

How do I stop fullscreen games from minimizing when I click on another window on my second monitor Windows 10?

In the game's graphics settings, set the game to run in Windowed or Borderless mode. This will prevent the game from minimizing when you click on your second monitor.

How to Move a Fullscreen Game Window to Another Monitor in Windows 10 [Tutorial]

Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.

Images: Olha Ruskykh, Brett Sayles, Andrea Piacquadio, cottonbro