@GameFan you would need to comply with the PD protocol and advertise the correct power to the device, and also support 5Vsafe to start negotiation of a PD contract.
You cannot just apply power to the type-c input as the laptop needs to know the charger power to prevent overloading the charger as we control the power envelope of the system based on the negotiated power contract.
I am a lot more excited about PD-Legacy charger adapters so I can continue to use my old laptops and only need type-c chargers :D.