Need a lean-and-mean formatting/publishing tool

I am writing nonfiction books. To-date, I've done them in Google docs, which with a little trial-and-error and manipulation, can usually create an OK-looking epub and pdf file for KDP. I'd grade the output at a B-. Definite limitations.

I've been researching Vellum / Atticus / Scrivener, etc. Problem is, so many of the features are geared toward fiction. Plots, storyline, etc. Stuff I really won't use at all.

What I really want is to be able to write my manuscript in Google docs, and then have a final formatting software/plug-in that can get the finished product quality from the B- up to an A+.

Also, I'm a Mac user by choice (which I believe is required for Vellum) and virtually all my writing is done while online with a good connection.

I do not ever see me writing fiction.

Suggestions? Your tips here are great, but this is my first-ever post on this Reddit.

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