Connecting Beam to projector

The Beam comes with a adapter for use with optical, and your projector has an optical output. So you should be able to connect the 2 sources to the projector with the projector optical connected to the Beam.

Are you planning on adding surround speakers? if so, you may want to check that your projector will pass through DD 5.1. There's a good chance it only outputs stereo. If that's the case you may want to get an hdmi splitter that outputs hdmi and optical.

Also, the Beam is designed for small to medium rooms. If you're using it for a larger room, I'd consider the playbar, even though it doesn't have voice control built in. You can always add Sonos One as surrounds to bring in Alexa or just get an echo.

Last point, since you said wiring is not an issue, does that mean that you have access behind the walls for wiring? If so, then I would probably consider putting speaker wires in the walls, just in case. And place power outlets where I may want to add sonos speakers later on.

You are right, it does not output surround sound. I will require a 4k av receiver for that.
I am thinking of just getting the playbar right now with an echo and connect it via the optical output .
I will leave outlets for the sonos play speakers and sub that I can add later if I decide to go for the av reciever. Although, it's a pretty standard bedroom so I don't really see the need for that. I think the playbar should be enough.

Not to throw more doubt on your plans, but for standard bedroom, the Beam is great. I have a beam in my bedroom (with 2 play:1s) and in my gameroom (with sub and 2 play:1s,a converted bedroom) and love them both. In my living room/kitchen area, which is much larger, I have the playbar and that's the right fit for that room.

And you won't need to get a 4k AV receiver. The receiver would only do anything that an hdmi switch with an optical output would do...at a much cheaper price.

1) So if I get a Beam and connect it to the projector with Optical Output and add 2 play:1s, will it sound good considering the projector does not output surround sound?

2) I thought that the av reciever can be used to project 5.1 surround sound (or 7.1).

1 - If the projector doesn't pass through DD 5.1 through it's optical port, then there is no way you'll get surround sound to the Beam, Playbar, or anything connected to that port. Unless you're talking about some sort of simulated surround sound.

2 - Along the lines of #1 above it can't do 5.1 or 7.1 if it's source doesn't provide it, sans a simulation of sorts.

Both the Beam and Playbar (and playbase) can take in a DD 5.1 signal through optical (or HDMI-ARC for the Beam) and play surround sound with 2 extra Sonos speakers without any additional equipment like a receiver. The point of getting an HDMI switch is to get a DD 5.1 signal from the sources (PS4 and set top box) to the Beam/playbar, bypassing the projector since it would effectively block the signal.

You could use an AV receiver to do the same thing as the HDMI switch (not in all cases though), but it would cost a lot more and take up more physical space. That AV receiver can power separate passive speakers, but cannot power Sonos speakers (active speakers). Basically, you can use Sonos speakers for home theatre or an AV receiver for a more traditional setup. You can't really combine both too well.

Last point, Sonos can't do anything beyond DD 5.1 for surround sound. No 7.1. no 9.1.2 and so on. If you want that it's better to go traditional. Again though, you're talking about a bedroom where the Beam by itself is probably enough (although I think you'd like play:1s as surrounds).

Yea, it's a little complicated, and that's somewhat unavoidable when dealing with projectors.

So in order to get 5.1 surround sound,
ps4 pro and STB input to HDMI switch.
HDMI switch will output to Projector AND Beam? How?
Does it output to Beam via HDMI or optical output?

If the projector can't pass through, yes. Since you don't want 5.1 right away, i wouldn't worry about a switch right now.

yeah the projector can't pass through but I am thinking of 5.1 now since it's cheaper with Beam instead of playbar.

So if I have a matrix switch, I can input my PS4 pro, set top box and fire TV and output it to my projector and Sonos beam, all with HDMI right?
And I'll be able to use the ARC from Sonos beam to control my PS4 and set top box and fire TV?

I don't think ARC will work through the HDMI switch. Apart from that, yes.