This takes me back. I remember learning all of this in high school, some decades ago now.

I distinctly remember the first time I hooked up a 555 timer, then it was decade counters, 741 op amps, logic gates and such, then learning the resistor colour codes and blowing up electrolytic capacitors on the bench supplies for fun.

For my 6th form Electronics project I built an 8-bit ADC, parallel to serial converter, then serial back to parallel and an 8-bit DAC as output all from discreet components and logic ICs.

The first half (input stage) was enough for the top grade, but I enjoyed it so much I spent most of my lunch times in the lab building more and more onto it.

I can feel that joy in OPs post.

I later went on to do my degree in Electronic Engineering.

Thanks for that piece of nostalgia and sharing the fun with us with such a wholesome project!