Using non-inverting amplifier and AB power amplifier (from TIP31, TIP32).
My frequency response (using AC analysis- Ltspice) at 4ohm 10Watt speaker shows this :
Your frequency response is dropping above only 6.5kHz.
Maybe your simulator software does not know how poor is a 52 years old 741 opamp and how low will be the output power from your amplifier.
10W into 4 ohms is 2.25A peak. The weak opamp and minimum spec'd transistors might produce only 150mA peak which is only 0.045W.
You need a half-decent modern audio opamp and power darlingtons or Sziklai pair transistors.
Here is your frequency response simulation spread out vertically so we can see its level dropping above 6.5kHz:
looks like you have plenty of phase margin, reduce your compensation cap size... a schematic would help, but it does look like overkill on the compensation cap.
and you don't have to go from DC to daylight on the AC sweep... 10hz-1Mhz is enough it will get you better scaling on both axes also, kep the phase margin scale in the picture too, it is important.
The old 741 opamp he is using was one of the first opamps to have the compensation capacitor built-in.
The old 741 opamp has a very poor slew rate that cuts highs when the level is high.