All time I alt+tab the game systematically crash
with an error:
Last Epoch - Unity 6000.0.42f1_feb9a7235030
Sorry but the forum does not allow me to upload the screenshot, but this is the error.
I found this post that saved me.
https://forum.lastepoch.com/t/pressing-alt-tab-causes-the-game-to-crash/80419
I have a 4080 and the issue was the Smooth Motion feature.
Just turning this off in the NVIDIA App fixed the issue for me as well.