Multiple (2 - 4) input Electronic load

I need an electronic load to test switching power supplky.
I'm looking at some interesting design with a processor.
I can design simple design with transistor and control amplifier.
Does not know, constant resistance and voltage mode.
Constructions comparable to professional loads are complex in hardware.
That's why I'm looking for a compromise

I have a design of double electroinic load, but it's a big profi design with over 30 amplifier and many accurate 0,1% resistors.
I myself thought of the complexity and physically never realized it :lol:

Thanks
I'm looking for something funny not the complexity analog design.
My idea is
N-MOSFET + driver amplifier + amplifer for measure current + amplifer for measurent voltago + error amplifier for Constant current mode + MCU with DAC and ADC may be digital loopback fr constant resistace mode and constan voltage mode.
True, I still did not think much about whether digital feedback would be fast enough
It's just such an idea

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For clarification.
For example STM32F334 have 1MSPS 12bit DAC and 5 MSPS 12 bit ADC if add any time for processing in MCU
can this Implement digital feedback with reaction time around 2us.
Unfortunately, I can not fully appreciate the use of this slow feedback for electronics loads. Analog amplifier have slew rate typical 15V/us , from this point of view, they are 2u terribly long, but from this point of view electronic load?

It depends on what requirements you have for the load. :razz:
Big profi electornic load have adjustable slew rate for example from 1A/ms to 5A/us in 12 rate level