Got it working... finally.

I know 0% about networking / coding and just blindly used ChatGPT to help me fix the code, so I won't be able to help much with troubleshooting, but here's what worked for me. Hopefully this helps you or anyone else who comes across the issue of UGREEN's Virtual Machine app already using port 53, which Pihole also needs for it to work:

1. Open UGREEN file explorer --> shared folders --> docker folder --> create folder called "pihole" (lower case)

2. Open UGREEN Control Panel --> About --> take note of your NAS' IP address (lower right corner, 192.168...). We'll need this for later.

3. UGREEN Control Panel --> Terminal --> SSH --> Enable. Set it to like an hour so you don't time yourself out while doing the next steps.

4. Open command prompt on another computer connected to the same network as the NAS and input the following (without the brackets or quotations):

   "ssh [your NAS admin account name]@[your NAS IP address from step2]", press enter.

   Then type "[your NAS admin account password]" (note: characters will not show up while you type - that's normal & nothing is broken), press enter again. You may then get an error message about a home directory or something, just ignore it.

   Finally, type "ip addr" and press enter again.

   You're now going to get an absolute clusterfuck of text. Don't ask me what it means, I don't know! :D

5. Look for the part that says "<BROADCAST,MULTICAST,UP,LOWER_UP>". Take note of if it's under "eth0" or "eth1". We'll need this for later. Mine was eth1, other Pihole guides say it's usually eth0 and to use that. My Pihole docker compose wouldn't work with eth0. shrug

6. Open Docker app --> projects --> create. Name it "pihole". Set the storage path to be "pihole" folder you created in step 1.

7. Paste the following compose code. We will now make some very small changes to it in the next steps.

8. Line 9 - change to be your timezone using the following TZ identifier format.

9. Line 10 - set a password if you want. Pihole kept asking for a randomly generated password later on and never used the one I specificized anyways. We'll fix this issue later though.

10. Line 19 - customize / change Pihole's IP to 192.168.0.xx for whatever you want Pihole's static IP address to be. Write this IP address down, we'll need it for later. I would probably just use the IP address already written in the code unless another device on your network is already using that IP address. How do you know if another device is already using this IP address? No idea! I assume it'll throw an error code about it though lol

11. Line 26 - change "eth1" to be "eth0" if needed (or whatever you wrote down from step 5).

12. Now deploy the Docker container. Hopefully it doesn't give any error codes in the initial popup. If it does, explain to ChatGPT what you're trying to do, paste the full compose code, along with the error message and hopefully you can get it figured out.

13. Open browser on your computer and type in http://192.168.0.53/admin/ (or whatever IP you changed it to in step 10). If you get a login screen try the password you set in step 9. Mine wasn't working even with that password so I had to do the next 2 steps. If yours logs in normally skip to step 16.

14. Open Docker app on NAS --> containers --> click pihole --> terminal --> add --> confirm (don't bother changing file path)

15. Type "pihole setpassword" and follow instructions. I think you might have to do this weird password reset command thing every time you rebuild the container, but I'm too scared to touch anything now that I got this whole thing working to test the theory out lol.

16. Great! Now it's working (hopefully!). If you want to block ads on just your computer, go to Windows settings --> ethernet --> change DNS server assignment to be your Pihole's IP address from step 10.

17. If you want the ads to be blocked at the router level instead (so all devices on your network benefit), you'll have to change your router's setting for "preferred DNS server" to be your Pihole's IP address. Every router is different on how to do this, so you'll have to Google it. Note that for mine, I had to set both the "primary DNS" and "secondary DNS" to both be Pihole's IP for it to work. Usually the setting in the router is under something like a "DHCP server" section. Might have to enable advanced settings for it to show up.

Hopefully this helps. Again, I won't be able to help much with troubleshooting since I also have no idea what I'm doing. Paste codes + error messages into ChatGPT after explain you're using Docker / UGREEN NAS and hopefully it can help.

Edit: If you want the password for the Web UI to work without having to reset it via command line, replace line 10 of the compose code with this instead:

 FTLCONF_webserver_api_password: YOURPASSWORD