1- P2P [like localbitcoins,HodlHodl,LocalMonero], BTC ATMs, for mixers Wasabi or Samourai Wallet.
2- Yes, Astaricon appears to be reputable based on positive reviews, but you should still conduct thorough research and verify details before making a purchase to ensure safety.
3- You can use your real address its perfectly fine because its a legal loophole thats how the deepweb markets works, however consider using a P.O. Box or a temporary address service as an alternative.
4- Using multiple ATMs and disguising your appearance can enhance anonymity, but always be cautious of local laws and potential risks associated with law enforcement tracking.