All you need is an MMDVM board and a Raspberry Pi loaded with Pi-Star. The pre-built “commercial” packages offer no advantage.
The Chinese boards are OK and well soldered, but QA is non existent. Mine had virtually zero RF out due to faulty RF filter components. The board came from eBay and is used on a Pi Zero W, they cost around $25 delivered. I laugh when I see the prices being asked by the ham dealers.
73 Dave