Oh! Thanks for the examples

I agree the switching frequency isn't super high, but I managed to get 10khz to 18khz when i was using a 47n cap on my breadboard, but yes there is ripple there, especially in higher/changing loads! But for my purposes I'll mark it as acceptable, seems to be okay usually, but "okay" is certainly not a high bar here. I haven't managed to have a collection of op-amps, LM358 are what i had on hand but I'll have to investigate getting something better!
As for the circuitsim i have not prepared it for simulation, I've built the circuit on breadboard before putting it in the circuit, here's what my newbie soldering work looks like

in the picture I'm powering an LED straight from it
I know I'm missing a lot of the technical knowledge around coils and buck regulator but I'm happy to learn from mistakes!
Edit: I think one of my issue with the 555 and why I decided to try without it is I couldn't get mine to oscillate stably at high frequencies, likely due to the breadboard stray capacitance