open Libre Office that has my documents.
LibreOffice doesn’t have your documents. It is your system (or you) having the documents.
Anyway, you did not mention your LibreOffice version, hence the only thing which could be said by now: LibreOffice version 7.0.3 should work and if you don’t have that version installed: Update!
If you have that version: Run
/Applications/LibreOffice.app/Contents/MacOS/soffice --safe-mode in a terminal and provide error messages you may get.
>Do you plan on upgrading for Big Sur
Question addressed incorrectly to “you”. We are users like you and hence you could have asked yourself. For planned releases see Release Plans (see also above about 7.0.3)
> They are also saved in iCloud if there is a way to open them with Pages.
Ask Apple about features of Pages and/or at least specify the file format you have used to save your files (
.odt or anything else like