Nextcloud; No Admin-Name set trough Install

My Goal for my Turris-Omnia is Nextcloud inside a OpenVpn-Network.
OpenVpn runs now with my Laptop (not now with my Mobile, but this i have to try later again…)

So my actual Problem:
During the Installation-process (, i clicked to fast.
So i set no Admin-Name, just the Password.
Now i can’t complete the Installation in the Browser.
Neither “Admin” nor an Empty Admin Input-field “” get accepted now.

I found Password-Reset Manual for Nextcloud here (, but i am not sure, how it works in my case. I am worry to mess up the whole installation, if i experiment to much.

Is there a Noob-suitable Reset, or total reinstall of Nextcloud? (Have no Data to loose at this Point)

try to remove and resintall it with opkg.