The Sonos Arc is a TV Home Theatre audio receiver/speaker and so the TV is usually the central hub in this situation. So everything ideally needs to connect and run through your TV.. The ‘test’ here, before you purchase the Sonos Arc, would be to try and connect all your available devices mentioned to the existing TV input ports (if practicable) leaving your TV’s HDMI Arc port for the sound-out to the Sonos Arc.
So try to connect all to the TV, so that their audio plays through your TV speakers and then add the Sonos Arc to that setup. BUT…
With all that said however, there are other ways to get audio to the Sonos Arc direct and without going through the TV .. the first is via the Apple Airplay2 protocol. If your laptop can output Airplay audio, then you can play that direct to the Sonos Arc, as it has built in Airplay compatibility.
As an aside, note too that the Arc can also play the many dozens of available audio sources that you will find in the Sonos App, as briefly mentioned here in this link …
https://support.sonos.com/s/article/3459
Anyhow, it’s also worth noting here, that ‘other’ Sonos products, like the Sonos Port, Amp and Five, each have line-in audio connections - these ‘separate’ Sonos devices, as an example, can accept analogue line-in stereo audio from your Laptop and other devices, like CD/MP3 players/Turntables etc. and are able to pass that audio to the Arc and any other Sonos Speaker/device… so that’s perhaps another route to look at, to get your laptop connected to the Sonos Arc.
And so last, but not least, the new Sonos Roam can accept a Bluetooth connection from mobiles/tablets/Laptops etc. that are capable of playing Bluetooth audio. The Roam can pass that audio to the Arc aswell via grouping options in the Sonos App.
So, as you can perhaps see, there are a variety of options there for you to peruse and consider, but I suspect the Sonos ‘family’ of products, correctly set in place alongside your existing hardware, can likely achieve the outcome you are looking for, even if your TV is not able to act as the central hub for connection of every devices you are looking to use with the Arc.