Levels in UE4

I want to create 2 levels in my arkanoid, for this I just copied the first level and inserted it (it turned out to be Level_2), and then added a couple of blueprints there. The problem is that my blueprints are linked to two levels (for example, spawn blocks).

How do I make it so that when one bluprint changes on one level, it doesn’t change on another?

It’s because the BPs are the same thing. Just copy one of the BPs and call it something else ( in the content browser ).

for simple game like arcanoid use game mode blueprint, keep game code there,
You should not keep code in level blueprint, you just have example why it is bad idea.