I wouldn't prune a 2 yr old Philadelphus @theluciblack, let it grow a bit.
@Meomye I would cut out the oldest stems down to the ground which should encourage new ones to grow then give it a feed.
@Meomye could you post a photo of your philadelphus then we can suggest options 😊
I think racine's is a different variety. It looks like it could be Manteau d'hermine, which is a much smaller, bushier variety with small double flowers,and brighter foliage. I just tip back the flowering stems a little after flowering, and cut back ones which are in the wrong place.Lovely when they get going