Why are my Frames Dropping After Export.

aronhdoge Posts: 7 Just Starting Out*
hello, all my footage in my project is 1920x1080.
the 1st Couple of exports were fine (YouTube1080p) but then i tried to export the project in YouTube2160 UHD. After this the dropping in fames started. I understand that the problem is cursed but exporting it in YouTube2160 UHD but When I try to re-export it in 1920x1080 the Fames Still Drop.

Is there anything I can do to fix these Fames ?

Thanks you :)