Running into a 404 that should be generated by a recently installed module would suggest to me that the installation hasn’t completed successfully. Try running through the following commands to ensure all is working as it should.
These are my goto commands whenever I install anything new
Run one line at a time as the “magento” user from the “magento root directory”:
rm -rf var/cache/* var/page_cache/* generated/code/* pub/static/* var/view_preprocessed/*
bin/magento setup:static-content:deploy en_US en_GB -f
en_GB with whatever locales you’re using.
*Only required if you run Redis