documents automatically saved as .odt and I can’t open them.
You don’t give us much information about your setup or your method of “opening” a document. For me, the best way to open an odt document is to start LibreOffice, select Writer, then use menu File → Open and navigate to the document desired. Does that work for you?
Further to the above, and in case you haven’t already noticed, documents opened by the suggested method (above) will thereafter appear in your LibreOffice Recent Documents list. Very convenient.