SDF artillery is now in play in several areas. For example, attacking Turkish military positions in Nusaybin.
https://www.google.com/maps/place/Nu...39!4d41.213997
The SDF doesn't have much big gun artillery. They mostly have mortars.
If I were the SDF, I'd send units across the border and take the fight to the Turks. Apparently this is in fact happening in the Syrian city of Afrin (which the Kurds abandoned to the Turks last year).