60 fps footage in 24 fps timeline choppy after export

Hi, 

I hope you can help. I've recorded a lot of footage in 60 FPS (59,94 fps). Both on a Canon EOS 250D (SL3) and a Mavic Air 2 drone.

When I import it to Premiere Pro and make a 24 FPS timeline (23,976) I've tried different things I've seen on youtube.

I've tried to use the interpreted footage where I change all the clips to 23,976 FPS to match the timeline.

I've also tried to make a 23,976 timeline and then just add to 59,94 clips directly to that.

Both look choppy after rendering. I do exactly like in the youtube-videos (there's a lot of them), but my footage still look choppy. 

And another question: Shouldn't I be able to set the speed of an 59,94 FPS to like 80% in the 23,976 FPS timeline? Or will it result in stuttering/choppiness if I don't take it all the way down to 40%?

My clip is perfectly smooth before editing in Premiere Pro.

I really don't know why it's choppy and I hope you can help. Let me know if you wan't to see the footage before and after edit or the Premiere Pro settings. 

Thanks