That's excellent! You guys should interact with Nextcloud or someone should try their hand at a Nextcloud App [1]. Nextcloud's solution to Google Docs & friends is via the integration of OnlyOffice[2], which requires a DocumentServer [3] to function in the context of Nextcloud. Even without the collaboration aspect, having LibreOffice work off WASM, without any extra infrastructure requirement would be an excellent edition to that ecosystem I think.
[1] https://apps.nextcloud.com/
[2] https://www.onlyoffice.com/
[3] https://github.com/ONLYOFFICE/DocumentServer