Yeah, I would like to have done it easier than that but I am doing to use the LM1036 anyway so this makes my audio processing one block and I may use a switched switcher for power too. There are OLD Skool tricks like capacity multipliers that make those devices perfectly workable to several amps with only Vcesat heat losses where the losses are largely ohmic and thus small. But the chip works and could even be PWM'd (with careful filtering) as the control voltage is under 5 V. and there isn't a simple attenuator for stereo audio that I've seen that is as easy to use as much or as little as you choose of. Sometimes there are choices and there are 'choices' the hardest part is finding the best long term choice.
Bob