Install Nginx As Reverse Proxy Alongside Apache2

I found a few links that may be able to assist you with this option. While I'm not familiar with this, it worth giving this a review and try.

https://www.howtoforge.com/tutorial/how-to-install-nginx-as-reverse-proxy-for-apache-on-ubuntu-16-04/
https://medium.com/@khandelwal12nidhi/setup-nginx-as-a-reverse-proxy-for-apache-server-f182bf0ab8d3

If you haven't done so already, I highly recommend backing up your server before giving this a try. We do have a Backup Service that you can subscribe to and the cost of the service depends on the size of your server's plan. Once this is enabled, take a manual snapshot job of your server then proceed to install and configure Nginx and Apache for your server.
Linode Backup Service
Taking A Manual Snapshot

Thank you so much adding the tags.

Have already been through the links as with many others for the subject. All is good when running on the same server and IP.

But none of the written material addresses when servers are running on different IPs and communicating with each other, and also when connecting via domain names in lieu of IP addresses.