Yes, installing Chrome by layering the downloaded RPM at runtime works. But you won’t get automatic updates without doing an uninstall-reinstall dance (sorry, can’t find the Fedora forum post that shows this at the moment).
After I did that, rpm-ostree upgrade failed when when there was a Chrome update, because it failed to install the updated RPM from the Chrome yum repo. I’ve observed that rpm-ostree will happily install directly from an RPM on disk, but for some reason it can’t handle an RPM it downloads from the repo.
@chicagonyc, are you getting automatic updates from Chrome? There was an update last week (to 124.0.6367.118 from 124.0.6367.91). Although the workaround I’ve baked in to my custom images are updating Chrome automatically now, I’d be happy to get rid of it if there’s a better way.