Paul Huysing wrote
rolling back to the previous version that worked would be handy.
I don't think this would be the case for a new plugin, but this should rather be a feature request for the core Extension Manager (to be reported on
GitHub).
You could do it manually for some plugins, i.e. whenever a plugin is on GitHub and the author is tagging their releases properly, you can copy and paste the download link into the "Manual Install" tab of the Extension Manager and overwrite the version that way.
E.g. downloads for old versions of the Wrap plugin are available here:
https://github.com/selfthinker/dokuwiki_plugin_wrap/releases