According to the manufacturer, the following hardware compatibility is given:

Compatible with HP EliteBook x360 1030 G3; HP EliteBook x360 1030 G4; HP EliteBook x360 1040 G5; HP EliteBook x360 1040 G6; HP Elite x2 1013 G3; HP Elite x2 G4; HP ZBook Studio x360 G5

Good day
Great laptop you have.
According to the following link(https://www.hp.com/ch-de...) the HP active PEN G3 should be compatible (scroll down a bit).
Otherwise create a support ticket on the HP support website.
I am not from HP and therefore cannot guarantee my statement (to the best of my knowledge).
Best regards

Unfortunately no idea if the pen works for Dragenfly G4 🤷‍♂️