permissions: LXC changes to the default non-root user

I am running an lxc container for an application, but I need to change the default user to the same as my host system. I set up the container following these instructions:

How to run graphics-accelerated GUI apps in LXD containers on your Ubuntu desktop

Is there a way to change the default non-root user from "ubuntu" to something else, e.g. ‘User1’?

I tried to add a user in the container, using

sudo adduser user1

but I can't log in from outside the container:

lxc exec gui1604 — sudo –user user1 –login
sudo: /sbin/bash: command not found 

Preferably, I would like to have the same permissions as the default user & # 39; ubuntu & # 39; and the home folder in the container as

 /home/user1/…

Thanks for your help!