Which controller model is it exactly? You don't require any additional software on the deck to connect peripherals via Bluetooth. I've connected even two different generations of Xbox wireless controllers at the same time with my deck without problems.
Are you properly putting the controller into pairing mode when trying to connect?
There's probably some form of regulation preventing you to install arbitrary software on your entertainment system, even when you are the manufacturer.
How would you make money if you can't control the platform? Investing in the fediverse is a terrible investment case.