As a long time LibreOffice user (and for a while contributor), I can honestly say that comparing MS Office, OnlyOffice Desktop Editor and LibreOffice with tabbed UI, objectively MS Office has the most polished UI, while LO the least, and I am talking about icons/toolbars size and placement, font size and such, see for yourself: https://imgur.com/a/uoWkW3Y (no goatse, I promise!)
On the other hand, at work, we had a few users with issues on their MS Office installs, each time I offered to install LO, everybody refused.
Maybe is not the best idea to have that many UI variants and not one of them polished to look professional, maybe focusing on one, maximum two, and making them shine would be better.