You might be overthinking it, as some quick testing with my setup and I was using deep links in the form:
adb shell am start -a android.intent.action.VIEW -d https://pluto.tv/en/live-tv/5b4e92e4694c027be6ecece1
I got the URLs by channel from the Pluto TV webpage, and had subtitles turned on already in the Pluto app. I use FireSticks, so I had the usual one time prompt regarding whether I wanted to open the link in the Pluto TV app, or using the Silk browser. The ID was definitely channel specific, as the show was joined in progress, and the ID didn't change when the program changed.