The Amp connected to the TV HDMI Arc port will give you 3.0/3.1(w/Sub) TV audio, which includes the phantom TV front center channel, or it will provide stereo music audio.

The other Amp/Speaker-pair, can be ‘bonded’ with the TV-connected-Amp to be used as TV surrounds (rear L/R channels) and used as ambient/full stereo audio for music playback.

If wanting to use the second Amp for TV audio, I would not recommend you ‘group’ the two Amps instead of ‘bonding’ them together, as you will likely experience a 30~75ms TV audio delay and encounter lip-sync issues in that configuration, although Sonos do provide some tools to reduce that delay “TV Dialog Sync” it can be ‘hit’ and ‘miss’ depending on the type of audio being output. PCM TV stereo output can usually be corrected, but you may continue to see the delay with Dolby Digital surround audio. Local Network conditions may also play a roll and your listening distance from the speakers. Music audio however is not affected by such a ‘grouping’ setup and will work fine.

There is no way I’m aware of that the second Amp, away from the TV, can be used for additional front surrounds in a HT setup, but note you can add two pairs of speakers to the first Amp connected to the TV ARC port to achieve that, if needed.

I hope that info. assists