Your questions about SoFi Hong Kong are answered here

There’s no guarantee that all shares in your account will be loaned through Lend and Earn 2.0 as there may not be a demand for certain shares.

The market rate fluctuates. If the market rate is too low, you may not receive any income even if the shares are being lent. If the market value of the loaned securities is low, you may not receive any income either.