ePub doesn’t display full Table of Content and doesn’t remember the last location

ePub files can’t show more than 3 levels of headings. For example, the following file has 5 levels of headings, but MarginNote only shows 3:

Link to the file in case you want to test and verify: https://www.dhammatalks.org/Archive/Writings/Ebooks/BMC1&2_220701.epub

Also, when I close the MarginNote and open it again, it doesn’t remember the last read location of the ePub, but jumping back to the current heading.
As MarginNote only shows three levels of headings, it becomes an annoyance to scroll back to the last read location.

It also seems that the last read location is stored on the ram or something as the same problem happens when I switch to several other apps before switching back to the ePub.

Here the TOC of the same ePub in Apple Books. I marked headings not shown in MarginNote with red lines: