I agree that LibreOffice is basically a non-starter in this competition, but I also think you are over-selling the MS support experience - most of the information online to help with Word/Excel is rudimentary garbage cluttering up the search space.

We need a set of stand-alone Office alternatives which are fully cross-platform (so, Electron), backwards compatible with Excel spreadsheets and also offering more advanced no-code functionality, and for the Word/PowerPoint equivalents something with the power of LaTeX but an easy to use WYSIWYG fall-back.

Is that really so much to ask?...