I created a new privileged user in webmin / webmin users and want to give ssh access and disable root.
However, access is denied when I try to connect via ssh. Is there a way to create a webmin user with SSH access (not a virtualmin/domain user).
If you want a system user, do not create it as a Webmin user. Create a System user, and then make it a Webmin user, too.
Webmin has its own users, which aren’t system users (they literally don’t exist in /etc/passwd), but that’s not what you want. So, create a system user (you can do that in the System->Users and Groups or using the command line useradd or adduser), and then in Webmin Users add the user with UNIX authentication.