I think the coin that will outlast every other coin in terms of privacy will be monero XMR. Monero is the most anonymous coin that exists in the crypto market. Monero has been in the market since 2014. Monero has rose upward the market slowly in the mean time to gain position in the top 10 coins in the market. Monero is a highly decentralized platform . I think deep onion is also a great coin with high privacy level though I haven’t done much research about deep onion so don’t exactly know much about it. So in my opinion XMR is good and has great potential.