Class A Audio Amp - Improving Efficiency With A Mosfet CCS
Class A Complementary FETs will always be a struggle with 1 BJT driver


low open loop gain, thus >10% THD even with negative feedback since it is very quadratic.
only get 16Vpp from a 24V supply.
loss of low-frequency response with a single supply requiring large Cap may have poor characteristics.
poor supply ripple rejection (hum etc)
too many pots that are critical to adjust for Vgs(th) and BJT supply variations


Consider:
Class AB complementary drain followers with OA


Using bipolar supply can drive 2 Ohm load easily.
OA gain reduces THD to 0.1%
microamp driver supply +/- 16V or more   ( to  can gain 8V headroom to get the rail to rail outputs.
low idle power
DC to 100kHz BW min.
excellent supply ripple rejection.



Simulation. Fixed SIM