Thank you for your time and consideration.

Not sure I understand if there’s a question here. Do you want the remote to control the TV only, and not the Sonos? Which TV do you have? Which FIOS remote? If it is working on the Sonos app (which probably means it’s working on the TV and communicating the information to the Sonos), what is the different behavior you’re looking for? Which Sonos do you have, and how is it connected to the TV? Have you contacted FIOS for more data?

You either need to use the CEC protocol if using the TV’s ARC/eARC connection or use an infrared remote if using the TV’s optical connection. Any infrared remote will work so see if your remote can switch to use that type of signal. The Sonos HT products can be setup to recognise such remotes as outlined in this Sonos support link:

https://support.sonos.com/en-us/article/control-sonos-home-theater-with-your-tv-remote