It seems that "cannot...too" means differently.
For example, "you cannot be too strict with him" means that you should be strict with him. Not necessarily.
What about "I was not able to walk. Fortunately, my electric wheelchair gave me lots of freedom.However, as I became older, I realized I couldn’t be too dependent on my electric wheelchair"?
This sentence seems contradictory to the rule. Should "too" be removed from this sentence? No, it's fine.
I learn on the book that if "cannot is followed by too", it just means the opposite.
For example, "You cannot be too careful when crossing a busy road." It means that you had better be careful when it comes to crossing a road.