Update - we solved it with this "gearhead" package check:

    fun isAndroidAutoAvailable(): Boolean {
        val packageManager = this.packageManager

        val packages = packageManager.getInstalledPackages(PackageManager.GET_SERVICES)
        for (packageInfo in packages) {
            packageInfo.services?.forEach { serviceInfo ->
                val serviceName = serviceInfo.name
                if (serviceName.contains("gearhead")) {
                    return true
                }
            }
        }

        return false
    }

I'm going to pay out some of the bounty to those that commented as it definitely helped us get to the solution - thanks guys! :)