LibreOffice apparently can't handle some of the advanced MS-specific ("DOCX") modifications from OOXML Strict (which strictly speaking doesn't actually exist) but it does a fairly good job with most of what people are likely to throw at it.
The developers put lots of work into reverse-engineering DOCX.
OpenOffice on the other hand, is just an old, old version of LibreOffice from before the famous schism:
https://www.reddit.com/r/software/co...s_libreoffice/