Unless DL is lying, OP is not due any delay/cancellation compensation under EC 261/2004. ATC delays are "extraordinary" and outside DL's control.

The $300 gift card is simply a customer service gesture which has nothing to do with EC 261/2004 and which OP should consider himself lucky to have under the circumstances.

OP is certainly free to pursue DL further, but unless OP has a reason to believe that DL is lying and that the reasons are otherwise, OP is going to lose and is wasting his time. The bottom feeder services such as AirHelp don't waste their time on pointless matters and will be quick to tell OP.

For those who want the US to enact something such as EC 261/2004, why not consider that no other jurisdiction other than Israel has done so. Those who feel that they must have the harm made up to them are free to purchase travel insurance. The rest do not need to subsidize this through higher fares.