Well, you could create a website on your server, that does reverse proxy to the plesk panel, the same way nginx does it to connect to the apache2.
This can easily be done via the panel itself and does not require manuell fiddeling with config files.
So, how to do it:
1) create a domain with the required name you'd like to access the panel with later on
2) under the hosting settings of this domain, disable all options (php, fastcgi, perl, statistics, etc.)
3) unter Apache & nginx settings disable the "Proxy mode" and add the following lines on "Addition nginx settings"
Code:
location / {
proxy_pass http://127.0.0.1:8880;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Accel-Internal /internal-nginx-static-location;
access_log off;
}
After that you can access the Panel via this domain/website
This method does also allow you to set up additional URLs to access the panel with, i.e. if you want to have seperate URLs for customers and secure them with an LE certificate.