Hello! Unfortunately, as of now, TikTok does not support uploading videos in 120 fps. The platform currently only supports videos up to 60 fps. So, even if you have a video recorded in 120 fps, TikTok will automatically convert it to 30 fps for playback on the app.
In the TikTok video you shared (), it's likely that the original video was recorded in 120 fps, but it was converted to 30 fps when uploaded to TikTok.
If you want to achieve a smoother look similar to 120 fps, you can try recording your videos in 60 fps and uploading them to TikTok. This will give you better quality and smoother motion compared to videos recorded in lower frame rates.
I hope this information helps! Let me know if you have any other questions.