My honest feedback below from the perspective of a hirer. I'll start by saying I hate takehome stuff, for exactly reasons like this. It wastes everyone's time. They're fine as a 'last step before hire' thing, but not as a filter.

1 - Too much chatter. Part of the assignment is using judgment and working in ambiguity. I probably would have ran with what was given enough to knock out something small and local in an evening or two. Asking questions is usually fine, they even welcomed it, but seems counter to the original ask.

2 - Writing and sharing a proposal seemed like way overkill. You have to remember that these companies are now getting hundreds if not thousands if not tens of thousands of applicants, that is a lot to deal with if everyone does so. I think it's a bit of a disconnect...you feel like you're going above and beyond and being thorough, they feel like it's being a bit long winded and wasting time. That probably explains the nonresponse.

3 - The finished product seemed functional, but seemed a bit overkill on the infra and polish. This is probably a good thing to work with you, but ended up wasting a lot of your time if not being selected, which was the case.

4 - Maybe I missed something, but the requirement asked for terminal inspired. I'm not quite sure precisely what they meant by that, but didn't see any possible interpretation of that in the result.

Anyways, hope you don't take it too negatively or personally - you obviously are a talented individual and moreso seem to really care about your work. Just wanted to play a little devil's advocate with a different perspective.