Thanks for reaching out via the Bose Community. Welcome to the site!
I am sorry to hear you are having issues with audio delays, but I'd be glad to help!
The SoundTouch 10 is not a television speaker, it does not carry the correct properties for a television speaker, and a key thing to note is that the SoundTouch 10 along with our other SoundTouch speakers (20 series, and 30) have a layer of active equalization to enhance the overall sound quality more-so to provide the best audio experience. This post-processing cannot be disabled and is what is causing the delay to the audio you are hearing. Put bluntly, the speaker just isn't meant for video or applications that require low latency (live music production as an example.)
Moving forward I would recommend not using the speaker in this manner, but if you wish to use a speaker for your television, I would certainly recommend checking out our soundbar line of products that will be perfect for your use-case.
If you have any further questions, do feel free to get back in touch, and if anyone else wishes to join in the discussion, please feel free!