Is it sufficient to regret a sin with sadness without crying, and is excessive rumination on Hell to achieve repentance considered extremism?

Contemplating Hell is a type of the commanded fear. Its classification as extremism, waswasah (whispers/obsessions), or uprightness is determined by its outcome. If it leads to obedience and abstaining from the forbidden, then it is praiseworthy. If it leaves no effect, then it is blameworthy. Fear is not an end in itself but a means, and it dissipates when the object of fear is removed. The praiseworthy, sincere fear restrains its possessor from Allah’s prohibitions. If it exceeds that, there is a fear of despair and hopelessness.

True fear is piety, abstaining from sins outwardly and inwardly.