Yes, have travelled quite a few times over there or around lately with my D-Ticket and there are currently weeks of works-a part gets a 3d or 4th track.
Best info is on mobil.nrw (probably only in german fully).
Also there is NO either VRR (Düsseldorf Rhein Ruhr) nor VRS (Rhein Sieg=Köln Bonn) fare between the 2, its NRW (the Land=province).
But that -for a normal full fare single- does not mean very much, as you can also just buy it from a machine (and then its local, so NO IC/ICE allowance).
However, if you had planned to use a network wide VRS ticket-for days-you will need to stop at first station In VRS-area and buy from the machine there-or check what app/web is available
The machine will/can also show timings for next trips/times, if you set it to.
Somehow-but double check yourself, I also think the the usual DIREct S-bahn from airport (rather dank stop just beside) to HBF=Main in Dús is out of use, due to very serious staff shortages. These may also mean that any timings found the day before will turn out worthless. It is what it is sadly for now.