Given the dominance of MS Office, the LibreOffice developers have devoted a lot of resources to the "filters" that read and write Microsoft proprietary file formats. (LibreOffice natively uses ISO 26300 "OpenDocument" file formats.) The result is that LibreOffice has a high degree of compatibility with MS Office; and each version of LibreOffice improves that compatibility. That compatibility isn't 100% perfect; but in most situations if you're collaborating with someone who uses MS Office they won't even notice you're not using a Microsoft product. The latest version of LibreOffice may be more compatible with the latest MS Office than the earlier versions of MS Office that some people still use.
That said, documents that rely the more advanced or esoteric features of MS Office may cause problems. As noted earlier, LibreOffice doesn't support Visual Basic for Applications, which will cause problems for an Office file that relies on macros. And one thing I've noticed recently is that the latest rental versions of MS Office use a new font (Aptos) by default. LibreOffice doesn't have that proprietary font, which makes documents look funny when LibreOffice attempts to use a substitute for that font. (Older versions of MS Office might have the same problem. I think much of the "necessity" for a new font has to do with encouraging users of old versions to start renting Office 365.) Fortunately, it's possible to find the Aptos fonts for download. They're standard TrueType fonts and work perfectly well with LibreOffice.