system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] I'm a Dark Wizard who wants to destroy the muggle world. Best way to do this?

I am completely unaffiliated to any order, previous dark wizard's regime, government organisation, I am completely on my own. 

I am a very skilled wizard if I say so myself, what I lack in natural aptitude or specialty I make up for in all around versatility, and a relentless desire to improve myself. Give me time and reason enough to learn a new spell or skill, and I'll be able to do it, you watch.

I want to be able to destroy the muggle world without arousing the suspicions of either them or the Wizarding world, if at all possible. Destruction of muggle civilisation is probably more accurate, I don't need them all dead, I just want their nations, governments, and basic societal structures collapsed and fallen into anarchy, bloodshed and chaos.

I've done everything I can to erase everything about my past, the Ministry knows nothing about me, I live completely secluded and self-sufficient from the rest of Wizarding society. Until I act, nobody knows I exist.

All I've got is my wand, made from Ebony with dragon heartstring. How do I best go about my mission?
gpt
Apparate into various government buildings and Imperio the heads of various governments, then give them commands that will result in the destruction of all major world governments. (If Potter-Era use thermonuclear weapons. if Newt-Era just arrange to crash the economies of every muggle nation, while arranging for social unrest so that muggle society will devolve back into the primitives they are after the loss of their economies, at this point you can finish them off at your leisure using the classic methods).
  
  
If for some reason you are too weak-willed to cast Unforgivables yourself, you can also achieve more or less the same effect (with slightly more danger to yourself) by brewing strong Love-potions and tons of Felix Felicis, you feed the love-potions to all world leaders then drink the Felicis yourself.

If all goes well (which it should, due to the Luck Potion) you should have set yourself up as a modern Helen Of Troy, with every world leader begging you for orders for just the tiniest smidgen of attention. of course for more \*ugh\* 'democratic' societies you may have to get them to continue trying to appear somewhat competent to avoid having them removed from office. the rest of the plan is the same as with imperio.