Docs is a new open-source collaborative text editor, intended as an alternative to Notion, Google Docs, Outline, and other similar web-based services. Interestingly, the project is being led by the governments of France and Germany.

Docs is a web-based collaborative writing tool, with the ability for multiple people to view and edit the same page simultaneously. Apple Pages and Microsoft Word have simultaneous editing capabilities, but new changes can sometimes take several seconds to show up for all editors, which isn’t great for real-time collaboration. The base version of LibreOffice doesn’t support online document editing at all, though the LibreOffice-based Collabora Online suite does have it.

nice. Now try to replace MS Excel

can leave ms365 soon?

If you only need a simple spreadsheet, Ethercalc is not bad.
https://ethercalc.net/

For more advanced visualization, probably Python or R.

obviously, when we talk about MS Excel, we're talking the full capability of Excel, included scripts, macros and integration support.
Theres a reason why MS Excel which is only available with MS Office, has no competition.
Its too powerful.