So I use styles/headings to do my chapters as they have actual names otherwise I prefer to format font a spacing and all that manually it makes it easier to transfer files when all that hidden formatting isn't there. Way less glitches.
First thing to note the only automatic formatting I use is auto tabs. Ebooks don't like them and to all first-time authors, it's a bitch removing many tabs. Don't hit the tab button. Just don't. 200 pages of deleting tabs is painful.