Any packaged .exe should automatically use the GPU (if necessary) upon launching it. It shouldn’t be something individual players will have to manually activate.
From my knowledge (and my own experience) after reading several topics on this forum, some newer laptops and beastly devices are having trouble running even the simplest GDevelop games because the game simply decides to ignore the GPU and would prefer using Internal processor(s).
As far as I can find this is not something GDevelop can control.
Electron (the technology used to make an exe from an GD project) by default tries to use a dedicated/discrete GPU, and only has options to disable that, rather than enable it. It is up to the OS at that point on what it utilizes at that point.
GDevelop wouldn’t be able to force it beyond what Electron allows, unfortunately.
This is just from what I can find, so if others have found resources outside of the above info, feel free to share.