There are several supported versions LibreOffice 7.1.1 and older.
Wonder if a slightly old LibreOffice 7.0.5(?) or before may work
with your old "AOO - files." (What are those A.O.O.'s, exactly??)
According to the official site, macOS 10.10 and newer, works with
7.1.1; and Old release versions, [7.0.5], 7.0.4, 6.4.7 ~ Plus newer "pre-
release" LibreOffice 7.1.2. (Even older versions in an archive; those
are no longer updated, are available.) Maybe contact their support?
(Also suggests LibreOffice native Apple Silicon version is in devel-
opment; so until that's ready, that might be used under Rosetta2.)
Should you be able to use backups to revert to an older macOS
then your Mac could then run 'Open Office' for Catalina?
Well, local time is about 2:30AM Sunday, and I'm going offline!