It took 3 4 hours to export why.?

I have videos screen recording from iPad pro 4k 

I create sequence fhd and edit this video it is about 17 minutes when I export it .. it took 3 4 5 hours why? I try to convert video . I found the same problem .. I use M1 Mac and i9 both of them take the same time ... any solution? I have 20 hours need to export .