I have a double experience:
I stopped flying in 1991 after 16 years and 640 hrs (because of kids and work).
At that time I was an instructor and was flying cross country (200-300 km, not often enough because of instruction).
A few years later, I purchased SFS4 (no Condor at that time) and flew rather regularly on my PC.
In 1998, I went back to a gliding club where I was allowed to solo after 3 hours and 6 landings with an instructor. After 4 local flights I did two 200 km cross-country flights
As my SFS4 configuration was moderately realistic (90's graphics, no force-feedback, no pedals, etc.), I did maintain some piloting skills, but I think the major benefit at that time was for cross-country where it helped to maintain decision making.
The following years I went on flying cross-country for a few years (regularly flying 300-400 km in LS4, Discus, Pégase, ASW24, etc. - missed the 500 by a few km) and stopped flying again in 2006 (880 hrs total)
I purchased C1 late 2016 but didn't fly that much (150 hrs in 1.5 yr) as I was a bit disappointed by the weather model (especially in mountains where I used to fly IRL) and I quickly purchased C2 when it was released (I now have more Condor hours than RL).
I have a force-feedback joystick and a set of pedals
Last summer I went back to the club where I started flying and had a local flight on the very same ASK13 on which I had my very first flight, 44 years later, give or take a few days.
As I was accompanied by an instructor, I was allowed to sit in the front seat.
He let me fly the plane all the flight after release, and he only took the controls at the end of the final glide because he wanted to touch down closer to the hangar.
In that case, I must say that I'm quite confident that Condor helped a lot keeping the piloting skills as it is quite realistic.
Frequently flying multiplayer with a TrackIR also helped maintaining the habit of looking out (VR would do the same)
As we stayed close to the airport I have no idea about the cross-country skills, but I see no reason why it wouldn't be similar, especially as the navigation tools are the same.