Sollte ich die Peitschen des letzten Jahres beschneiden, um sie noch hedgy zu machen?

I’m trying to work out what species this is but kinda stumped (pun intended)… Kinda looks like honeysuckle (?) but the bark is too dark. Anywho.

It depends on how high you wnat the hedge to be. You should prune at slightly below (~15cm/6″) the intended height of the hedge. This will force the plant to branch out. Each successive pruning of new growth should be slightly higher until a dense plane of growth is achieved. This will of course take many years, but such is the way of whips.