How to enable 5.1 ch and Dolby digital in PC with Soundbar

I have bought Soundbar with 5.1ch & Dolby Digital I have connected it to my desktop using Optical cable, is there anything more need to to get most out of it? here is few queries I have:

• iam not getting the 5.1 option in spatial sound(output is selected to the sound bar) it just shows headphones there.(images attached)
• how to know that 5.1ch & Dolby digital working correctly?

Here is my PC specification: Intel® Core™ i5-12400F Processor ASUS TUF GAMING B660M-PLUS D4 Adata XPG Spectrix D50 RGB 16GB (8GBx2) DDR4 3200MHz ZOTAC GAMING GeForce RTX 3070 Ti Trinity OCCrucial MX500 500GB 6.35 cm (2.5-inch) SSD Antec HCG-1000-EXTREME SMPS Antec DF600 Flux DEEPCOOL GAMMAXX 400 V2 Blue LED air CPU Cooler OS: Windows 10

Soundbar: MOTOROLA AmphisoundX Vibe Dolby Digital 500 W Bluetooth Soundbar (Black, 5.1 Channel)

Optical Cable: https://zebronics.com/products/zeb-oc150