Tailscale reinstallation issues on Synology NAS

I recently used Synology Migration Assistant to transfer my entire DS1621+ to a new DS1821+ with new drives. The process seemed to go pretty well until I got to Tailscale. Tailscale didn’t like the two NAS units as they were using the same config (?), and rather stupidly I uninstalled from both NAS’s thinking a clean install of the package would eleviate the issues. I’d forgotten that when reinstalling Tailscale (after uninstalling) that there is an issue with the Login not automatically appearing, and the need to use a Terminal script.

I followed the directions in this YouTube vid which got me as far as connecting to the NAS. But when I ran the ‘sudo tailscale up’ command it asks for a password. No matter which password I enter it says sorry, or if I just hit enter with no password, it asks again. I’ve seen there might be some issues with passwords and credentials needing to be in the Apple Keychain? But I just can’t seem to get beyond this?

For the moment I am using the default SSH (which I will then disable once this is done). And I have changed the logins to just be just password (single-factor). I’m not a power user, and the SpaceRex channel and forum have been instrumental in getting me this far! I’m hoping I can get some help, so any advice would be great!