It would be helpful to know which reverse proxy you are using. I use HAProxy but there are countless others including Nginx, Unit or Apache can also be used as a reverse proxy. And the configuration is different for everyone.
And of course if you switch from PHP to static and you have a dynamic page with PHP, then it can no longer work. But why should it be necessary to set it to static?
Forwarding to a Docker container on a subdomain in the aaPanel with the reverse proxy seems to work. But whether you can also forward to a subfolder of the main domain is not quite clear to me.
Normally it should be possible with a reverse proxy, even if you can’t do it in the aaPanel.
But you should perhaps ask directly in the forum for aaPanel.