I need help with metamask, i have some old erc-20 address(public, lost private key) and i have 400UNI on.
I feel sorry for you man, you should know that private key is everything you lose it and you lose all the coins that are associated with your wallet
it's hard to admit that by losing the private key you also lose coins that could be worth $5000 in the future, try to remember where you place it, don't lose hope.