I had this problem as well. I have done this before and was successful. However, I did shoot on a Ninja that time. When trying this time, I am also importing to find that Premiere is seeing 29.97.
So, I just took my original clip and imported into Adobe Media Encoder. I changed the frame rate to 59.94 and the field order to Progressive (no fields). I exported that and got pretty smooth footage.
I then imported into Premiere and the clip read 59.94 and played back pretty well. Then, I went rt-clicked on the clip and selected Modify / Interpret Footage and set it to “assume this frame rate” or whatever and set it to 24 fps.
I am pretty sure I used another method last time, but I am not sure. However, this method seemed to work quite well even though it included another step. The end product is pretty smooth.