How to make timelines' framerate over 120fps?

Hello, I am an editor that often use high framerate videos and footages are mostly over 120fps. But I cannot change timelines' framerate over 120fps. I want to something like "cut and add some fx then export (keep the same fps)" but could not, as I tried these days.
So can I get to know how to achieve this?

I don't think you can.

Do you really want to show more than 120 fps or are these shots for slo-mo?

Do you really want to show more than 120 fps or are these shots for slo-mo?

Mostly for blending multiple frames. 480->60 each 8 frames blend together to get a nice motion blur effect. DR does not offer real `frame blend` option, but I cannot even set my timeline to over 120fps.

[Peter Chamberlain]

The studio version has Optical flow processing so set your timeline to 60fps and place your 480 fps clip into the timeline.