Weed is not going to ruin your life the same way like benzos and alcohol would. If you smoke everyday then you probably aren’t very productive, but you are not actively ruining your life.
Weed is dangerous because of how safe it is. It makes you ok with being bored and not progressing/growing as a person. Alcohol addiction will straight up make you homeless.
C is the way to go my friend. The popular languages such as Python which you mentioned, are just C in a trench coat. It’s all abstraction. If you understand C, you will be able to understand any language.