I think I feel similarly to you.

M currently re-writing an app that I wrote years ago. All the issues came from data structures, queries, architecture that didn’t fit what emerged as the use case.

Now I can focus on those things and work far faster, and even ADJUST architecture, theorize about pros and cons of changes as I work … sometimes I find that some adjustments are easier than I thought.

The result is far faster development, and a more optimal result where I can stay focused on improvements / efficiency rather than random minutia.