Hi, I am new here. A veteran webserver admin but until now I choose the easy route Plesk for my servers. Digital independence thoughts and ever rising prices brought me back to taking things for my servers in my own hands. After moving away from Plesk, I chose ISPconfig to manage my servers. It's powerful and flexible, but many of the sites I run are tightly coupled to Apache. So I needed a solution to run nginx as a proxy in front of ISPConfigs apache without inhibiting its functionality in any way, as my customers have the freedom to add and remove domains and all functions should be unattended by me as much as possible. So I wrote myself a solution that helps me installing it on my servers. I refined it into a reusable install script and uploaded it on github. I had about 2min of downtime at most on my servers, switching nginx in as a reverse proxy. As I am new here, I may not link. You can find it on Github with this search word ispconfig-nginx-reverse-proxy-solution. If a person with link rights would link it below, that would be awesome. Have fun with it.
Btw, there is also an ISPConfig plugin for that: https://git.ispconfig.org/ispconfig/ispconfig3/-/merge_requests/1703 But I'm not sure if this plugin still works in the current ISPConfig version. It might need some updates.