I can't enable or disable a user service: Failed to execute operation: No such file or directory

Symlink issue?

I had a similar error message when using symbolic links.

Apparently systemd doesn't follow symbolic links, the solution is simply to copy or move the file.

User service?

I believe that you need to add --user to the command line for units in user/:

sudo systemctl --user enable arkos-redis.service

In my case, I was placing my systemd unit files directly under /etc/systemd/system/... folders. Moved them to /lib/systemd/system instead and that resolved the issue with systemctl enable/disable commands.