But i2p doesnt have PoW DDOS protection. Trust me, that shit helps a fuckton for limiting ddos. I witnessed firsthand nine onion services that upgraded from not having DDOS protection to having DDOS protection while under attack and the attack completely stopped.

Edit: RetoSwap, a decentralized Monero exchange, has 9 onion seed nodes and they were being DDOSed to oblivion. As soon as they added PoW the attacks stopped and havent happened since. That was about 9 months ago now.