If you blindly buy a high premium ETF, even if the index tracked by ETF does not fall, the premium rate of ETF price will decrease, which will also lead to investors' losses.
For example, the net value of ETF is 1.00 yuan. If you buy an ETF at 1.05 yuan (a premium of 5%), the ETF price will approach the net value when the premium disappears, but the investors who bought the ETF before will still lose 5%.