I have a feeling that this human step might be at the end of a chain of automated filters.

No, only the local FS. But they have recommendations in their README for integrating with S3 with the help of other tools.

You are invited to join the CopyParty! This has a web UI accessible from the browser, also from mobile, files are stored directly on the filesystem (not encrypted or on a database) and you can mount it as a network drive on Windows and Linux. But it doesn’t let you sync files for offline use, at least not without the help of some auxiliary tools.

You won’t find anything simpler to install and configure than this.

Here’s my config for reference, which works for me:

name: forgejo
services:
  forgejo:
    image: codeberg.org/forgejo/forgejo:12
    environment:
      - USER_UID=1000
      - USER_GID=1000
    restart: always
    volumes:
      - ./data:/data
      - /etc/timezone:/etc/timezone:ro
      - /etc/localtime:/etc/localtime:ro
    ports:
      #- 80:3000
      - 2222:22
    networks:
      - nginx
networks:
  nginx:
    name: nginx
    external: true

If you can share your error message we might be able to better pinpoint the issue.

EDIT: I searched a bit and now I understand better what you are trying to do. I didn’t know about this “SSH shim” idea. This is not what I have done on my setup, sorry.

They provide decent defaults for all the not-so-straightforward configurations, and they provide a web UI to configure the rest. That’s the sole reason I would recommend it to get one’s feet wet without having to work too much.

If one is committed to do things “the right way” they could switch to Nginx and “proper” self-hosting later.

I would say this would be the proper way to do it (at least as a sysadmin), but since it’s OP’s first time I would simplify it to:

1. Install CloudFlare ZeroTrust daemon on your local server;
2. Set up reverse proxy such as Nginx (optional, the alternative is to use a different subdomain for each service, which might be easier);
3. Point the FQDN to CloudFlare.

Let CloudFlare handle the certificates, DDoS protection, etc… Link if you’d like to give this setup a try.