1) Are you a Sun Direct customer?
2) Is your TV an Android TV?
If your answer to both these questions is 'yes', then you can try downloading the SunNXT app to your TV (from your Android TV's Google Playstore), login to the app with your Sun Direct registered mobile number and see if the Dolby Digital audio works there.
In the JioTV+ app, did you try Comedy Central HD? (under VOOT Premium)
In Sun Direct, the STB's EPG for the Comedy Central HD channel says that it has Dolby Digital audio. It is a long shot, but it wouldn't hurt to give it a try.
I don't think any of those channels are Dolby on OTT. The STB should support Dolby audio bro, but there's no content through which you can check it now.
I don't think any of those channels are Dolby on OTT. The STB should support Dolby audio bro, but there's no content through which you can check it now.