The DSC9S soundbar is officially designed for the C-Series OLED evo C2, C3 and C4 and comes with a special Synergy Bracket developed for these models. There is no explicit compatibility specification for the OLED C5 from 2018, but in principle the soundbar works with any TV that has HDMI ARC/eARC or optical output. However, the special bracket only fits the models mentioned.

If you are using the OLED C5 from 2018, the soundbar is compatible as long as you connect it via HDMI or optical. The Synergy bracket is not intended for your model.