UcD Switching wavefoarms

So I've been playing with a ucd in microcap and started to wonder if the high-side fet can handle this kind of voltage swing regarding the IRFB4020PbF has a gate to source voltage of +/- 20 V, any insight into this matter or any. Feel free to ask questions 🙂
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ClassD wavefoarms.JPG
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Although the absolute maximum gate-drive voltage might be 20V, it is recommended that this be limited to about 12-15V, as the stress on the gate oxide layer would be high and the insignificant benefit due from deeper enhancement of the device is not worth the risk of having a reduced overall reliability.

Besides, the gate-driver switching power dissipation is also proportional to the square of this voltage, which means that the dissipation at 20V is already double that at 14.14V gate-drive.
 
VGS would normally be 0V/10V-15V to avoid wasting energy in the gate drive. Whats the objective of this design? I would change a number of things:
1) Use IC half bridge gate driver
2) Different output MOSFETs IRFB4020PbF is quite old with relatively high Rdson.
 
Never tried ucd, if I need on low frequency bass like 2hz to 100hz , is that good (ucd?) or tpa3116,irs,etc performance much better, don't need high frequency, class ab sounds better 🤔