Raspberry Pi4
Openhabian - OH 4.3.2
I would like to change the username in a template I created previously so changing in openhabian.conf won’t have any effect. I understand the the password can be changed in the openhabian console but not the username. Is there a file I can edit to make this change or something?
No.
You can reinstall and set the username on install, but changing admin user is pointless.
You really are asking for trouble when you attempt to.
What you can do is create a new user. But you cannot easily just change a username. But you have to make sure all the same permissions and such get added to this new user. If you do this make very sure that the new user works for everything you need before deleting the old user. And of course I’m sure openHABian will have some issues as well.