I might break it down as: if you know C/C++, I'd start with a microcontroller [Arduino, ESP32, RP2040/2350, etc]; if you know Python, there are still micros that run it, but a full Pi might be an easier starting point for you. (Either way, if you end up doing this for more than a year, you're going to eventually do both...)
Don't think of the microcontroller storage specs in relation to a modern PC. I use an EV CAN diagnostics tool that runs on an ATmega328 (32K of program storage and 2K of RAM).
Few (except maybe dmitrygr!) would recommend a microcontroller today if your goal were to build a spreadsheet or word processor app. But you'd be amazed how much business logic you can stuff into such a small space, as long as your requirements are focused.