Definitely would need to increase FPS and it wouldn’t be the most time efficient solution either but you could create a TW clip with motion estimation.say at 10% (that’s be slow enough), do the time displace slit screen effect using a horizontal gradient then you speed up the result by 1000% when you’re done. Or TW to 5%, do the slitscreen with TW displace then speed it up 2000%.
It might me be a fiddly approach but it is effectively what rolling shutter is doing so would give accurate results. Of course, you’re likely to get artefacts in the motion estimated slow down but depending on the rolling shutter effect you are after, that could add to making the effect look more real. The ML time warp could also work well for this too but you’d have to pick the right speed up at the end.