alt Hacker NewsOnlyOffice, Nextcloud OPffice, Collabora might all have free offerings to a degree, but you'll end up at the mercy of the companies behind those tools and OnlyOffice comes with Enterprise offering that does also cost money.
Costing money isn't necessarily bad, but it's also hard to beat free & libre.
True.
But I have to say that I got quite used to collaborative editing, not something I'd like to give up.
People can get used to buttons moving to other places (imo), but collecting and integrating edits from multiple people via email is not something I look back at fondly.