Actually wants to know about any waiting rooms at Dusseldorf station

You can check here:

https://www.bahnhof.de/bahnhof-en/D-C3-BCsseldorf-Hbf-3804134

There are NONE as such-no IndRail  here with 1st/2nd/3d/4th class tier etc.-here is an awfully dirty and always taken by homeless people sitting area just behind the info-counter in main entry hall (city side), it has free wifi and just beside the IBIS HTL. that takes part of the station building. This is becse on every line-this is not IndRail here-trains run at least a few times/hr. so there is no real need for-as is also in about all major stations in Germany or for that matter even in the whole of West_EUR. I´ve passed there at last 10 times the last 3 monthes.

IF you maybe have to bridge time for a few hrs due to check out and time of train-much better to spend a few € and just sit in some cafe/restrt. OR see this town-which has quite an attractive centre 4-5 stops on the underground trammetro away from main station. (NOT included in pass-its city transit Rheinbahn)

I was there 1.5 months ago and although it could do with some cleaning, it was certainly not "awfully dirty”.