[WIP] Define better errors with thiserror

[windy1]

What

Brief summary of these changes and their impact. The easier it is to follow and understand, the easier to review.

Why

Reason for these changes. And why not some other changes (if applicable). Context here can be helpful when later blaming this code/reading logs.

Manual Tests

What did you do to verify your changes?

Documentation Updates

Did you document the purpose of any new code? Did you add comments explaining anything that might look strange to
someone trying to figure out what your code is doing a year from now who doesn't know the full context? Is the README
for this repo still accurate and useful?