Today I would choose a soundbar with rear speakers from LG - hindsight is wiser ;-). About a year ago, I couldn't order the rear speakers individually from digitec, so I ordered them from Amazon.de. The model was LG SPQ8-S wireless rear speakers (140 watts) for the LG soundbars DS90QY & DS80QY, Dark Steel Silver [model year 2022]. plus 2 speaker stands. It works perfectly.

The LG SPQ8-S rear speakers are a good match for the DSC9S (in a 14m2 room) in terms of design and performance.

The statement that the LG SPQ8-S is a wireless rear speaker set is only partly true, as the two speakers are coupled via a receiver, but the speakers have to be connected to the transmitter unit by cable (passive speakers).

Unfortunately, the DSC9S & SPQ8-S combination did not convince me in terms of sound.
But that's mainly because I have the wrong LG TV, namely the OLED55C9PLA. However, the LG DSC9S is only optimal for the LG OLED evo series from 2021/22 (according to test reports and my own experience).
As far as I have read, there are no other wireless boxes that fit the DSC9S. (P.s. I'm happy to be corrected here).

The operation and setup of the LG DSC9S is simple and should not pose any major problems even for technical laymen. The instructions included are minimal, but you can find everything very quickly online or via the app.

I'm about to return the SPQ8-S set to Alternate, so if you need it, I can let you have it with a small discount as it's brand new.

LG SPQ8-S 1 pair of wireless rear speakers (140 watts) for the LG Soundbars DS90QY & DS80QY, Dark Steel Silver [model year 2022] for 75 euros at Amazon