I don’t recommend my workflow 
unless you have a specific need like mine (I tend to spend a lot of time on a single book, so it balances out):
- Right click epub > extract (you may need to rename to .zip, or use 7zip)
- Create an index page in obsidian, copy and past the TOC page
- For each chapter, create a page, link from TOC page
- For each chapter, copy and paste into obsidan
- Find and replace all epub links with obsidian links
When it comes to referencing, then I just hit [[^^ to find the paragraph.
Picture are usually in the “resources” folder, so I just use ![[ to inline these.
Re. Formatting, most of my books (corporate strategy, philosophy and psychology) comes across just fine, however, textbooks do not - I haven’t figured this out yet…