You really need to take the cvt cover off and have a look inside to see if there is anything obvious wrong on theret
Check the belt, take off the clutch bell and clutch and check them and the clutch springs for any damage.
Take off the variator and check that for damage, check the rampplate and its plastic guides (plate behind variator to hold rollers in).
With the cover off you can turn the rear wheel by hand and see if anything rubs at the clutch.
Could be any number of things, without stripping it down it would be hard to guess.