The circuit kinda works, but it leaves a lot to be desired. There's 3 areas that I'd like to improve:

• Input - catches a lot of switching noise going from around ##V (nothing connected) to over 3Vpp once buck converter goes berzerk, around 11V input
• Output ripple - it’s too unstable to be called buck converter. There’s 2.5V of ripple present on the output measurements
• Output floating with input voltage - currently, output will float for about 0.5V when input voltage changes from 6V to 12V. Ideally, there should be no floating

Capacitances

I think the part where I can improve the most is tweaking input/output capacitances. So I grabbed all of my capacitors and started playing around.

Currently, my physical circuit features only one 10uF input capacitor and one output 33uF capacitor. So I set input voltage to 13V (well in the region where ripple is high) and started testing different capacitors. Trial an error (table below) gave 47u as the best available option.

Or graphically