The subscription is just a Ring subscription, which you can bundle with Ring doorbells, cameras, and security system. It doesn't cost much.

I just noticed that the Amazon Astro is now available for purchase without an invitation.
https://www.amazon.com/Amazon-Astro-for-Business-mobile-security-robot/dp/B0BX1HG85N

It's a whopping $2349!!!

I bought one more than a year ago when I received an invitation. I was not impressed. It was buggy and felt like there was a disconnect between the Astro robot side and the Alexa side of things. Also the loud click-clack noise it made as it rolled around the kitchen tiles at night was annoying. The two big wheels are rubberized and dampen the sound. But the single plastic wheel in the rear is what makes it really annoying. It's been over a year, so i don't know what improvements Amazon has made.

I can control everything in my Alexa eco system, With my car infotainment system... even when not in the same zip code... I Don't think it matters which device is on what Ghz, or wifi router, as long as the router/access point is permitted access. On the other hand, if you have some Hue bulbs set up as Blue tooth devices, it may not control them the same due to the non/wifi connection. That's a user choice generally. If it requires a bridge for full features, I can almost guarantee it will require the bridge for full access by other devices.

Keep in mind though, I have a 2023 Honda Accord, with Alexa built in. I had to give the car access to my Alexa account, and my Google account for maps and Alexa connectivity. This stuff with me in the car... not sure if my phone has to be with me or not, except for Apple Car Play functions.

you should be able to select which wifi network to connect to during the setup process.   

Hi All
I have 3 Wifi networks at my place, one of these is close to an Alexa but when I set up on the app it basically connects to whichever wifi the phone is connected to which could mean it is trying to connect to the wrong one in another room.

Is there a way to hardcode it so it only connects to a static access point/network?