Are there variable which shows the document level.
For ex. i don’t want to use breadcrumbs if document level is lower than 3
There isn’t a document variable that will tell you this, no. You’d need to write a simple snippet to get this info or modify your breadcrumbs or other snippet to check depth. Take a look at the UltimateParent snippet for an example of how to traverse upwards from a document to the root (that snippet could be modified to output a depth variable).