On my newest build, I installed a Propex heater and a Partner stove. The stove needed a high-pressure regulator and the heater the standard 11" WC like your BBQ uses.
Plan A was black pipe. But I recruited a friend of mine that was a propane installer for thirty years. He suggested rubber propane line. He said copper can work harden with vibration and wasn't enthused about all the fittings it would take for pipe and the possible leaks. I'm quite glad I followed his advice.
Any propane store can cut the rubber and add the 1/4" female pipe fittings.
The line coming off the red regulator which is 27 PSI is motor-vehicle propane line which is reinforced with steel mesh.
It's easy to fish the line wherever it's needed.
Tony