It will be ok but it is not ideal. You will especially miss out on any height channel effects from the Arc’s two upward-firing drivers. Ideally the Arc should be placed closer to ear height.

Surely the heat from the fire may also affect your TV? Perhaps consider just using the fire for its visual effect only and find other ways to heat the room and then put the Sonos Arc below the TV, or use some kind of shelving in between to try to deflect the heat away from the A/V devices.

Hi Ken,

I just pull out the tv 20 cm from the wall. And no problem

Mov the Arc to a mount connected to the back of the TV so it moves with the TV.

https://www.sonos.com/en-us/shop/sanus-tv-mount-arc

Do check your temperature limits on that TV, many are not supposed to get very warm even when not in use.