How is the default nice value of a user's processes implemented in Ubuntu server 22.04.4 LTS

I've noticed that all services and processes with my user in Ubuntu Server 22.04.4 LTS have a nice value of 19. I connect to the server through ssh, and my ssh sessions also have a nice value of 19. I didn't use the nice or renice commands. I'm searching for the configuration that produces this default nice value. So far, I've seen that /etc/security/limits.conf is the place to configure default nice value, but my current file is all commented out. Also I cannot find any reference to this nice value in the generic systemd user@.service or user.slice unit files. In desktop Ubuntu, the default nice value is 0, so I assume it must be configurable. Could you point me to the configuration file where this nice value of 19 is configured?