People always say this but the 90% doesn’t count. The 90% is easy. It’s the other bit that people hit and compatibility issues mean any non standard approach whether it’s fair or not will always, always get the blame.

Plus I dispute that libreoffice has even close to 90% of what excel can do.

Let's not compare the advanced options of Excel or how Excel bugs annoy me. There are loads of them.

Let's just compare what people do when they need a tool like Excel. That's when the 90 or maybe more % of people will do. That is what I do. Everything I do in Excel can be done on LibreCalc.

So it is true that LibreCalc can replace 90% or more, because not everybody needs those advanced topics.

Same for the other LibreOffice apps, Writer is good for almost everybody. As LibreDraw and others.

I’ve never met a document an office document that wouldn’t have been better as a wiki (if it is intended to be impermanent), or as a something like a LaTeX document (if it is not).

Doesn’t matter what you think (or I). The real world runs on MS Office.

I've found that OnlyOffice has much better Microsoft Office compatibility. I just install it via flatpak, remove the network permission, and go about my business perfectly. While LibreOffice -> LibreOffice works perfectly fine, whenever it opens a .docx file it always wants to save it as a .odf which is a nonstarter. Not because I don't want to support open document formats but because everyone expects a .docx back if they send you one. It also struggles consistently for any type of advanced formatting (as a .docx).

Remove the network permission by what mechanism? I only know firejail or this (iirc)

install via flatpak (which uses bubblewrap iirc for sandboxing) and use flatseal to remove the network permission. You can also manually edit this through .local/share/flatpak/overrides.