As I said you have to check the box to allow all users in the settings to get NM to load at boot not just when a user logs on. It is not clear to me you have done this.
And I agree not a good idea to have /root on it’s own partition . It is where it is for good reasons. Also looks like you dump a lot of thing there also. Root is a special user and should be treated as special. Do not use root as a normal user would it use their directories. In fact you should never ever log into a GUI as root. You will break stuff. Only become root from a normal user login using su or other of the family