I understand how you’re feeling. I totally get how frustrating it is when you’ve put in so much time and effort into something, and then it gets rejected. I’m sure they’re flooded with submissions, so it takes a lot of time to process them all. It seems like the MegaGrant initiative isn’t a high priority for Epic now, so the team involved is probably small. We waited several months before someone reached out to us, and then waited another few months before we finally got rejected with the Unreal Bucket project. At first, it was demotivating and felt like a waste of time for our team. However, we took that as a lesson and improved our “promo materials”.
Anyway, don’t give up on your project if you believe in it. Keep up the good work and enjoy the process.
Good luck! 
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