Have you perhaps looked at using a Sonos Amp for the front L/R and phantom center channels? See this link:
https://support.sonos.com/s/article/4717
The Amp can connect to the TV over HDMI ARC, or Optical, and also be used with another Amp, or Sonos speakers for the rear L/R surround channels and the setup will support upto two Sonos Subs (one of which must be a gen3 Sub).
A Sonos Amp uses two ‘front’ speaker to create a virtual center channel, in addition to the stand left and right channels, when fed a 5.1 signal. It requires a pair of third party speakers to be connected to it. Is that what you’re looking for?
Either another Amp, or a pair of like Sonos speakers can then be used as surrounds, if desired, as can a Sonos Sub.