I’m so sorry, I said “it was working on windows” to indicate that my touchpad supports multitouch, and it’s not a hardware issue.
I hate windows and I will not use it again, I’m using Linux for 2 years since I know it.
I read the whole article trying what is recommended, I found Synaptics is deprecated and not supported.
libinput working properly only with two fingers, so any gestures software (touchegg, fusuma, libinput-gesutres, etc.) does not receive any swipe signal
Warning:xf86-input-synaptics is no longer actively updated. If possible, use libinput. For some reasons why you might still prefer xf86-input-synaptics, see, e.g. [1] and [2].
That, to me, is not the same as: depreciated and not supported
But then there is the blue box right below that red box:
Note: If you want to configure touchpad via GNOME Settings, you need to use the libinput driver.[3]
Which means (to me) that there is no point in using synaptics - not when you are on Gnome, that is.
I have no solution or informed and tested advice to offer.