This is an absolute make or break feature for me. I am trying out the free version, but unless there is support for ODS, then it's definitely a show-stopper.

Proton, we need this feature please !!

... as soon as you can do it, Proton!
ODT viewer, at least, por favor.

I wondered about ODT support the moment I tried Docs for the first time, but hey I didn't expect DOCX support out of the box. The Proton Docs ofcourse have their own format as well which can technically be developed to suite the needs and specific approaches for Proton services and expand features that they can't just add to other formats. Innovative features and specifics that properly work and have cross-functionality with Drive and perhaps even Mail are welcome ofcourse.

Still, ODT support for at least just previewing could come sooner rather than later so it's something wait for more Proton specific features, which I'm fine with taking a bit longer so they're even better when introduced.

This is probably the only real show-stopper for me which keeps me from switching over from Google Drive and a mix-and-(mis)match of self-hosted solutions. Most (if not all) of my documents are ODF.

now that proton added support for .docx files (https://proton.me/blog/docs-proton-drive) and simple markdown/txt files, open documents should be top prio for drive!

I can't believe there is still no preview for open document format files.
(still awesome that there is finally doc support)

This is an important feature, especially in Proton Drive. I suspect that Proton users have an above average preference for open source software. This is why it's is surprising to me that Microsoft Office files can be previewed, while OpenDocument files can't. I'm also surprised that this idea hasn't received more votes yet.

This could potentially be done via the open-source web app ONLYOFFICE.

Please, add support for ODT. I'm replacing Microsoft Office with Libre Office, and a Proton Drive Viewer for ODT is something that should be there from the start. Thanks!