It’s an abbreviation – yyds – of 永远的神（yong yuan de shen). The words in bracket is ‘pinyin’. Chinese monosyllabic pronunciations can be rendered in Roman letters using a system called pinyin.
“yyds,” the pinyin abbreviation of Chinese “永远的神,” is originated from ． eSports player Shiny Ruo when he shouted out “Uzi, 永远的神!” to his idol Uzi, a retired League of Legends player.
Maybe it’s just like ‘G.O.A.T.’ in English.
G.O.A.T. =Greatest Of All Time
Eg.“I think LeBron James is the greatest all-around basketball player ever. To me, James is a GOAT.”
= ’James, yyds!’