k4j8

Caddy has this feature built-in. It looks nice too.

recipes.local {
	root * /srv
	file_server
}

https://caddyserver.com/docs/caddyfile/directives/file_server

There's also File Browser.

wg-easy

Agree, highly recommend this and/or Tailscale.

Great list! If you already have the Raspberry Pi devices, great. If you were going to buy some, I would look at thin clients instead. Low-power, cheaper, more powerful, can use real hard drives instead of SD cards or adapters, and x86 instead of ARM. I have an HP T630 I like but I hear good things about the Dell Wyse 5070 too.

I really like Vikunja and use it individually both personally and professionally. It meets all of your criteria except tracking hours. They have a nice demo too: https://try.vikunja.io/.

I was going to say that Finamp doesn't support offline filtering by artists, but when looking for the open issue I just found out the beta does support this! Awesome!

As others have said, Nextcloud for files/calendar and Tailscale for VPN is your answer.

Nextcloud can be installed in several ways, one of which is Docker Compose. Docker Compose is flexible but requires learning a bit, although you can use it for most self-hosted software.

We’ve integrated a new REST API and embedded web server directly into the pihole-FTL binary. This eliminates the need for lighttpd and PHP, reducing the installation footprint and boosting performance.

Very nice!

I host Caddy and Vaultwarden using Docker. The traffic into the reverse proxy, Caddy, works over port 443, not 1808 or 1443. Using the Caddyfile, you can tell Caddy which port to send the traffic over.

Caddy docker-compose.yml

services:
  caddy:
    ports:
      - "80:80"
      - "443:443"

Caddyfile, although there are other ways to do this

*.example.com {
        @vaultwarden host vaultwarden.example.com
        handle @vaultwarden {
                reverse_proxy :11808
        }

Vaultwarden docker-compose.yml

services:
  vaultwarden:
    ports:
      - 11808:80

I think it's cool you're trying to find ways to get into this. If the goal is to learn, why not deploy the services on your laptop? They won't be available when the computer is off of course, but you would still get the full experience. Even a low-spec laptop will be better than a cheap VPS.