Windows defender flags your games as dangerous, or the game engine(s)? Is it only on your computer, or every computer?
If it's only on your computer, than it could be your window defender settings. I have not used windows for a while now, so maybe something's changed? I've never had any issues with Windows defender for my games, or at least no one has reported having any issues. Given it happens no matter the engine, I would guess it's your Windows defender settings.
If it happens on other computers, then it might be different. It is probably that the other computers Windows defender settings are similar/same as your computer. (Default windows defender settings?).
Or it could be something is injecting malicious code. The odds that something is injecting malicious code is really low, like under one percent, so I highly doubt that is the case but I suppose it's theoretically possible... Or it could be something else entirely, who knows!
Regardless, I suppose you can tell Windows defender to make an exclusion, see this Microsoft support page for info on how to do that.