I searched this community and couldn’t find anything about odt, I found a few odt viewers on F-Droid and Aurora when I searched ‘odt’, but the only editors for odt, were ironically the proprietary Google Documents and Microsoft Word.
Have you found anything else?
I’ve been using Collabora Office recently, you can get it through F-Droid but you have to add their repo
Another user also recommended that and it’s been working great!