If you want to access CyberPanel on SSL you can do so by issuing Lets Encrypt SSL for hostname, before continuing further make sure you have created website with a domain you want to access CyberPanel as.
If you want to access CyberPanel on: https://panel.yourdomain.com:8090 , create an account with domain
panel.yourdomain.com. While creating an account you can either check SSL or not, it is optional.
If domain still does not point to the server, again a self-signed SSL will be issued.
Main > SSL > Hostname SSL
Select domain on which you want to access CyberPanel. Once issued, you can visit CyberPanel on https://yourdomain.com.
Note: If you also want to host websites on this domain, you can do so by simply using FTP or File manager, this operation will not affect that.