Touchpad inactive after gestures configuration

I wanted to activate additional gestures on my Dell Vostro laptop, but I did worse than better because my touchpad no longer works at all.
It’s a PS / 2 Generic Mouse but I don’t know if it should use the Synaptics or Libinput drivers.
I tried to uninstall one or the other, I even lost my keyboard, which I found since phew! But the touchpad could not find it.
I’m on Ubunutu 20.04