A Sonos Amp and six Sonos outdoor speakers by Sonance.

Give them both a look at the Sonos Store

https://www.sonos.com/en-us/shop/outdoor-speaker-pair

https://www.sonos.com/en-us/shop/amp

https://www.sonos.com/en-us/shop/amp-and-outdoor-set

Essentially this is a very large “room”. I recommend adding subwoofer.

Does the Sonos Amp support dual Subs?

Sonos doesn’t make that clear, just saying “Home Theater System” here.

https://support.sonos.com/en-us/article/set-up-your-sonos-sub?language=en_US

That would sound really good with one at either side of the doors.

I am far from an expert in Sonos, but recently was at a friend’s and he had 1 Sonos Amp with the Sonance Mag 6.1 System on his screened-in porch which has a higher ceiling and is much larger than what you have pictured.  It sounded AMAZING with good volume and bass - it is what has me now trying to figure out what all to get for my new construction build and into Sonos.  

Sonance - MAG6.1 - Mag Series 6.1-Ch. Landscape Outdoor Speaker System Powered by Sonos