The chord progression generator doesn't return correct chords, as it uses the Chromatic scale, while it should probably use a diatonic scale.

So for example for I-IV-V it gives me C, D#, E while it should give me C-F-G (https://www.justbuildthings.com/chord-progression-generator)

This should be easy to fix, though. To point you in the right direction, see e.g. - https://en.wikipedia.org/wiki/Roman_numeral_analysis - https://en.wikipedia.org/wiki/Chord_progression

Fascinating topic, keep up the work!