This is being communicated for RHV and RHGS in their communication channels.

As for oVirt and Gluster, there's no EOL announced

The Hyperconverged guide for oVirt has been moved from the main documentation section to https://ovirt.org/dropped/gluster-hyperconverged/ as nobody is still maintaining it and it doesn't fit the rest of the content of the doc directory (docs are asciidoc, this guide is still markdown).

Also, being Gluster storage deprecated for RHV I would expect testing in this area to be reduced by Red Hat QE but this doesn't mean that for oVIrt someone else can step in and provide the testing coverage for this storage type. The code for handling Gluster and Hyperconverged is not going to be removed as far as I know.