Yeah I know it’s a tough situation and it sucks really knowing you’ve put that much into these. The best option is to really stay on a version of the engine that is stable for you if you don’t absolutely need any of the newer features. If you do, then test and see if you run into these kinds of things before moving over to the next release for full development. Understandably you may already do that, but just something to always keep in mind.
That being said, there’s a lot of variables with the number of sub-levels, the number of actors included, using HLODs, etc that I may spend an hour or so attempting to reproduce and not get there. Don’t get me wrong, I’m not trying to dismiss this, it’s just a lot of things going on that without much steps to reliably reproduce or have a test project that reproduces the driver crash is hard to play guess work with a setup. I hope that makes sense.
From your other post I see that you do have multiple computers to test on. That’s a good starting point to rule out if the reflection capture updates after being moved actually do cause the display driver to crash. You can move them in the editor level and then go to the Build button in the toolbar and use the dropdown to select “Update Reflection Captures.” If it crashes then, that could be something going on there with the RCs. Also, you didn’t mention, but are you using the default reflection capture cubemap resolution of 128 or have you changed this to be higher? If it’s higher, lower it back down. These can easily cause VRam to run out causing the display driver crash.