他姓易但不容易

This username reads as 'He’s surnamed Yi but he’s not easy to obtain'. It humorously conveys that although someone named Yi appears casual, they are hard to get or have. It adds a layer of sarcasm by playing on the similarity between the word for 'easy' (易 - yì), which is also used as a Chinese surname, with someone who might seem approachable but isn’t.