Yes, leveling too low can give you very strong adhesion. It’s worth noting that PEI beds tend to lose adhesion as they and the print cool down. I can remove cooled prints without much effort off my bed, bit hot prints take some more convincing.

You can set nozzle distance with a mechanical feeler, like your sticky note, but you will need to fine tune some based on things like extrusion temperature and type of filament. This guide was made for printers with auto bed leveling, but the pictures are helpful.

Here are some signs you’re too close to the bed:

• a ripply first layer
• areas of the first layer with no filament and/or a clicking extruder motor (your nozzle is too close to the bed and can’t extrude at all)
• elephant’s foot (the first few layers stick out more horizontally than the layers above them
• a thin and brittle skirt that flakes off in pieces vs coming off as a continuous loop. Removing these tends to leave a very thin layer of residual material on your bed that you can see, but not really feel
• layer lines that are too smooshed together