Grammarly FOSS alternative: https://languagetool.org/ Multilanguage (It recognizes which one are you using, that is very useful for me as I use 3 - Catalan, Castilian, and English -) and it is sponsored by the European Union

Of course, they are OASIS, you only have to save them as ODF or the OASIS kind of file, edit offline and update or sync with LibreOffice https://www.libreoffice.org/ and others compatible https://code.google.com/archive/p/ooo2gd/

As they export/import to/from MSO, you can even use MSO, but some features are not compatible

Also, Collabora Office for Android and IOS compatible devices works, https://www.collaboraoffice.com/

Transparency happened, because 2.000 USD in a business is not even a developer monthly salary. And if they must discuss for that it is a sign that money is not wasted in luxuries. I think that using internal affairs to attack any distro or business use is a nonsense.