First of all, I have to mention that, here in the community are some incredibly kind people who gave me some great, and well needed feedback.
They even sent me their logs, and that's helped me a lot.
Thank you!
It was completely random and very rare, but the game some times crashed without any actual reason and you only got a UE4 message.
The save system thankfully worked in this situation every time.
It turned out my game had some memory leakage issues in my level streaming system, that I was finally able to fix.
I've done some research and it happened basically most of the Unreal games in the past, but, it is very rare.
My fix to this issue was to load most of my assets in to the RAM when you see the UE4 logo on the launch, so now the game here loads up a "fake map" randomly filled with these assets.
I've tested it with 8 and 4 GB of RAM and it worked fine every time.
Also, the game now has a 16:10 monitor support, and I also fixed many small technical and graphical bugs.
I basically updated my game two or three times a day in its lifetime.
Who do you think he is?
