Help please with my paph venustum

[andreaemilia]

Hello

I got one pah venustum but is not doing well
I received it tths sping along a paph Lowii, a gratrixianum and a maudie vinicolor
the others are doing great, they shared the same space and conditions, but the venustum arrived with very short roots, it grew one and a half new leaves but no signs of root growh
I put Clonex on the roots to promote growt, kept it a little more humid since the roots seemed to dry rapidly beeing so superficial, put it under the growing lamps
its not dying but it isn't thriving either
I put it in a smaller pot, with bark and perlite mix, around 20 grad Celsius and relative hunidity 50-60%
I checked the roota there are not rotted

any ideas???
I would appreciate the help
PS The yellowish tint of the pictures is from the grow lights