Testing on my own site with WooCommerce 9.1.2 and WordPress 6.6 the plugin is working correctly. I recommend that you give Health Check a try in this case. Health Check is a tool that can be useful for debugging, though it requires an official default theme like Twenty Seventeen. On the troubleshooting tab, you can click the button to disable all plugins and change the theme for you while you’re logged in to that session, without affecting normal visitors to your site. This will let you try the Regenerate Thumbnails plugin on its own, without any other plugins active, to see if it works. If it does, you can then re-enable plugins one by one, testing after each to see which isn’t compatible with the plugin.
Not all plugins and themes are compatible with Regenerate Thumbnails.
