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Anyone can edit it and it also might get randomly corrupted. It’s crap, especially if some people are on Macs.

I haven't used any but there are several it seems: https://european-alternatives.eu/alternative-to/google-docs

NextCloud looks ok.

For some reason I thought it was open to the public, but France also maintains a full sovereign cloud office suite for use by civil servants: https://lasuite.numerique.gouv.fr/en

Maybe one day they'll open it up publicly.

Open-Xchange supports collaborative editing of spreadsheets. Mailbox.org uses that for their email service, and you get access to their online office suite when you subscribe. I can't speak to the quality of the shared editing, but their online office suite is fine for basic stuff.

Zoho.