The blueberries... I have no idea what those are.

Looks like blackthorn - śliwa tarnina - a close cousin of plum, cherry, peach etc. An immortal "you shall not pass" bush - very dense, with plenty of small hard branches that act like thorns. Great place for small birds. Hard to get rid of if you let one grow where you don't want it.

Wait until after the fruits had a chance to become frozen and then pick them up for tasty liqueur 😋