To me, in reviewing the ADE information and the actual approach plates for URSS, none of this makes any sense.
If FS was basing any of the arrivals on real world charts, there would be NO fixed wing landings on 20 or 24.
All the instrument approaches are for 04 or 06, with no circling weather depicted, meaning, no circling to land on 20 or 24.
This is due to multiple terrain obstructions NE of the field.
And the missed approaches are for a climbing turn ( away from those obstacles).
Also there are no approach lighting systems nor VASI/PAPI for 20 or 24.
And the extensive airport remark data pages make no reference to VFR or IFR landing on 20 or 24, only take offs.
So, the landings on 20 may be an FS default coding (airport or traffic) with no bearing on real world operations and possibly non-adjustable with ADE.
You even stated that " By default, ATC use 02 for landings and take-offs." which is not what apparently happens at the actual airfield.
This is just a guess on what is happening.
I do hope you find a way to make this work appropriately, i.e. TO/Dpt = 20/24, Aprch/Lnd = 04/06.
Ref: https://opennav.com/airport/URSS