When you open a level, the only actor that persists is the Game Instance. New level means a new instance of the game mode - your data resets.
Also, are you sure you want to cascade branches like this? What if you have 100 levels?
Why not use what I suggested - the Next Level actor has a level name variable - make it Instance Editable so you can do this in every level:
And then you can have the Next Level actor open a new level, like so, bottom right:
This way any level can lead to any other level. You can even have multiple exits or have a level chosen at random!
If you do not want to do it like this, have the Level List array in the Game Instance instead and increase index by one every time the level changes, fetching the appropriate level name.