Error in compensator for buck
Your schematic will also need an anti-shoot-through circuit that prevents the two MOSFETs both being active at the same time. I've replaced the superfluous VCVS (E2) with that addition shown as a simple red block: -

And, the actual additional circuit can look something like this: -

It provides a little bit of dead-time between one MOSFET turning off and the other turning on. That dead-time is controlled by the RC network shown above. Picture from here.
And, if you were implementing it in your circuit you could get rid of the inverter (U8) and do this: -

Note that I'm now using an OR gate and a NAND gate in the anti-shoot-through implementation above. You may need to play about with the implementation a bit to make sure I haven't introduced an inversion somewhere but that's fairly trivial.