Hi,
you shared logs, but there is still no clear overview of your actual setup (docker configuration, NPM configuration, networking layout, etc.). Without understanding how your environment is structured, it’s very difficult to tell whether this is a configuration issue or something else.
I would strongly recommend going through this deployment guide and comparing your setup step by step:
It describes a working reference architecture for Nextcloud AIO behind a reverse proxy (including networking, ports, proxy configuration and general layout).
Please compare your configuration against that guide and adjust anything that differs.
That should help you verify whether your issue is caused by a misconfiguration.