"I wonder how much I'm actually destroying my health by smoking weed every day, drinking coffee, and having some alcohol at least in a minor capacity."

Probably not at all. Cue the "correlation isn't causality" soundbite, but coffee consumption is negatively correlated with developing Parkinson's disease, and moderate consumption of alcohol has been shown by many studies to correlate with positive cardiovascular status. Haven't researched the literature on associations of weed with positive health outcomes, but it's interesting that smoking weed doesn't correlate with developing lung cancer.

You're probably just fine so long as moderation is your mode.