hi,
for all users that are not registered @xda or 4pda..
here are some nice Magisk Moduls for the Mi6
60fps.zip = enable 60/120fps
60fps_hevc = same above, but videos are recorded in hevc format
240fpsMiui10.zip = enable 60/120fps and 240fps@720p slowmotion (miui10 only)(beta, will be updated...