Yeah, probably you aren't very experienced with flurry rushes, but i actually mastered them by lynel hunting so just keep going. For all weapon attacks (except for that one when the lynel jumps with his spear, perfect guard is better for that one), flurry rush is the best way to counter them...
I actually defeat lynels via flurry rushes because usually i spend the master sword and one weapon and then i get another weapon so no losses for me. If it still has some hp left i urbosa it.
I recommend you to get stasis+ asap, by giving 3 ancient cores to Purah, then by stasising and hitting enemies you can cancel any kind of attacks (even the ones from the final boss), and it can help fighting against the lynel (even though i dont recommend you going for it now, wait at least till...