Tried installing unity desktop, now black screen at login

Hi, I need help please. I would like to know how to restore my desktop. I wanted to try unity desktop, so I did

`apt install ubuntu-unity-desktop`

Now every time I reboot and reach the login, I have a black screen. I have to do

systemctl restart lightdm

I see the login screen has been replaced by unity configuration.

Also when I finally reach the mate desktop, the window decoration and cursor config are messed up.

I’ve made progress. I override lightdm settings by adding these line in /etc/lightdm/lightdm.conf

user-session=mate
greeter-session=slick-greeter

Now I have a normal login screen, but once logged in there is a black screen. I only have the cursor. But when I switch back and forth from a console, the desktop finally shows up.