Congratz on the purchase Komple… one of the things I see all the time is Code saying, did you compile using the GitHub version of the engine. Not the engine that comes with the Epic Launcher. Now, I know next to nothing about this whole thing. but, a have seen CS say, “You have to use the Engine that you download from GitHub.”
Might start there if you have not used the GITHUB source. CodeS is really good about answering questions. As well as others here.
Again, welcome to the club.