Some consumer devices allow streaming apps to force an input change. They do this by running apps that advertise a particular capability, like AirPlay or Cast, for example. Those apps can then cause a number of actions to occur if a client app initiates a streaming action over these protocols.
If this is functionality you desire, you should be looking for a consumer device that already advertises having this capability built in. Boutique high end music servers are the wrong class of devices to look to.
I believe the manufacturers of consumer devices actually have to pay royalties to provide support for some of these capabilities. This cost is then factored into the selling cost of the device. I believe this is why none of the boutique music servers actually support the official version of Apple AirPlay. To provide this capability, they rely on an open source variant that can only provide a subset of capabilities. I wouldn’t be surprised to learn that Spotify Connect on Antipodes is accommodated through use of an open source app.
Cost isn’t the only determining factor in why open source apps are chosen. The official app may place demands on the product that are unacceptable. The Antipodes Player should be running only what’s needed and nothing more for best sound quality. Apps that need to run all the time so they can listen for particular protocols shouldn’t be running on the player engine of a high end music server.