(The connected experiences, including Copilot, can be disabled with a dialog hidden deep in Office's Trust Center, but even that's confusingly worded. It's unclear from the wording and the structure of the dialog what the combination of checking "all connected experiences" but unchecking "experiences that analyze your content" should actually do, for example.)
MS Office is certainly the more polished product, especially Excel. There are some spreadsheets I can't feasibly convert to LibreOffice Calc without equivalents to Excel's lambdas and tables.
But LibreOffice does the job in most cases. I'm really excited to see this new work—especially CRDT-based sync between desktop app instances over a network file server, which would turn LibreOffice into a significantly better experience than MS Office for my purposes.