Various stylistic edits

This MR is a bunch of stylistic edits.

The draft is very long, and I think it could benefit from removing some of the repetitive bloat (in text and in titles, using shorter sentences, and generally being less verbose. These changes are an attempt to make it more readable. It removes some hurdles that I faced when reading it.

See the individual commits for why I think the respective changes make sense. I'm happy to drop or edit them.

This MR also fixes a logic typo and reorganises a section for clarity.