The Syrian Democratic Forces (SDF) and its subdivisions such as the YPG and YPJ have never in their history launched a military attack against Turkish territory. In fact, the Autonomous Administration of North and East Syria (AANES) is a very good neighbor of Turkey. The AKP regime accuses the SDF of terrorism, yet the SDF has no history of terrorism whatsoever. It is rather Turkey that terrorizes the AANES and ethnically cleansed the Kurdish Afrin enclave in northwest Syria on the border with Turkey. Turkey occupies parts of northern Syria for no reason whatsoever, this is pure aggression by Turkey against Syria and the AANES.
The SDF however needs to be given the means to defend itself. The AANES should be allowed to purchase Western heavy weaponry as far as it can afford to and should even be granted US foreign aid toward this end. It’s certainly a US interest to contain the AKP regime promoted Jihadist expansionism in North and East Syria (NES).