My 2020 Alante came with a Soundstream radio. Yours is a much better system. I replaced the Soundstream in mine with a Sony AX-XAV-5000, which is almost identical to your unit.
The Sony XAV radios do not have power switches. They are intended to come on automatically when you power up your vehicle. This is done via 1 Amp line from the acc switch on your vehicle to the radio. When that line is on, the radio powers up.
The rub with our Alante motorhome is that when the house power is on, that activates the acc line too - so you can enjoy music via the house battery instead of the coach battery.
Since the radio itself has no power button, that means that if the coach battery is online, your radio will be on, and draining your battery. I got around this by putting an on-off switch on the acc line - a rocker switch I installed on the panel. Now I can manually turn it off when I want to, on either battery.
I am certainly not an expert. This is just an old Montana cowboy's solution after doing my own research, so please do your research on it and/or get your tech involved. All the best with your new coach!