The Sonos Amp will be a very good drop in replacement that will also make the Sonos Connect redundant. But no more, so unless you don't have anymore the space to keep the Yamaha, you may as well continue with it.

My Sonos Amp drives two B&W floorstanders. I recently tried a Pioneer amp and honestly couldn’t tell any difference in sound. Both are excellent! I decided to continue using the Sonos Amp and brought the Pioneer back. What you gain with the Sonos is a much smaller, very good looking amp that can even be installed on a wall behind something, or discreetly on top of a stand or table.

Also: I have found Yamaha amps to be very well built from a reliability perspective; I have one that is stashed away in a ventilated box paired to a Connect for my patio system, and I haven’t even seen it for many years now - it just works so reliably.

So if space isn't a constraint, there is no need to make a change and take a chance - however slim - with any new product failure issues.

And almost certainly, for pure audio applications, the Yamaha will be more versatile for multiple input handling than the Sonos Amp.