Kali GUI disappear after tweaking UID and groups

Hi there, I've recently renamed my main user and changed its group. I believe I messed a bit things.

The results is that now:
a) If i log in straight with the screwed users, it misses all the GUI, icons, menu and wallpaper. Only a plain standard bkg and a terminal window (see screenshot)
b) If i log to another user, then i do a user switch, I find everything in place

Don't think this is much related to the update && upgrade I've done short before that event, nor that the configuration (Kali on VirtualBox) has much to do with that; otherwise, even the second account would not work.

And in fact, when I list users in the working account (attached), I see there is still the old account (the main before renamed) somewhere.

I'd like to kindly ask for suggestions to repair this. Thanks a lot!

I'd become root.
as user
sudo passwd root
new password" <type new root password> and again
su -
password:

type "id" make sure you're root.
deinstall your user. Save off anything you want to save to /root/<user's name> directory
remove the user and all its directories and config files.
Maybe boot up the usb installer image and see if it will let you pick the user installer section so that it applies whatever install scripts to create that user.
You could just tar off or save off all your user data, and just run the install again.
It's easy enough to create a user and home directory, but how the install scripts modify the particulars- permissions, etc. is key.

Couple more thoughts:

1) Recall the steps you did to change UID and GUID and reverse them. Set them back.
Can be hard if you were typing away.
Did you use a "-R" for recursively changing things- such as chown -R or chgrp -R as root? That's dangerous. World of hurt.

2) If you don't want to just reinstall Kali, after saving the user data elsewhere and deleting the user and directory, you could , I suppose, mount the installer usb and traverse down and see if you can find and decipher the user-installer shell scripts. There must be shell scripts where you could see the prompts and what admin commands it runs to treat the new user. Tedious, but could be helpful. Use view on the script if you're good with vi movement.