Hello, Welcome to the Forums.
You’ve posted this in the ‘Unreal Engine’ “Getting Started & Setup” section, I’ve moved this to the ‘Fortnite Developer’ section.
It’s generally advisable to focus a thread on one specific topic. Also it’s possible to create bug reports in the Fortnite section.
I’ve seen creators complaining about their maps slowing down after running for a while(hours?), I’m not aware of anything that can be done to improve or fix it, but if you can reliably reproduce it, it may be worthy of a bug report, or appending your findings to an existing bug report.
For the ‘Draw’ issue - I searched the UEFN section for the word ‘Draw’ and found a thread with some info/tips.