Big PMOS wants more gate drive than a 10K resistor can
source. Consider making another, smaller version of the
circuit as the main PMOS shunt, driven antiphase.
All you really need is an "on" resistance well lower than
ZL of the PA, right? You could get that for about 50 cents
from any power MOSFET driver, bare output, and hardly
any RF circuitry operates at drain voltages greater than
you can find a power MOSFET driver or purpose-made
drain switch / load switch IC for.
A proper level shifting power MOSFET driver for PMOS
high side, might not cost you much more than your low
side NMOSFET. And you often get two per package, so
you could (say) have independent Tx / Rx enable.