Your questions about SoFi Hong Kong are answered here

When you make a sell trade from the HK market, it’ll take 2 business days (T+2) to settle. While you make a sell trade from the US market, it’ll take 1 business day (T+1) to settle. This amount will be shown as ‘Net Unsettled’ under ‘Account Value’ (Menu -> Account -> click downward arrow under ‘Account Value’ to show the whole breakdown of your funds). On the third business day (T+3) for sell trades in the Hong Kong market and on the second business day (T+2) for sell trades in the US market, you will be able to see it as ‘Cash Balance’ and you can submit a withdrawal request to transfer funds back into your registered bank account. You will have to wait until this day to withdraw the amount. Cut-off times and transfer processing time apply for fund withdrawals.

You can find your ‘Buying Power’ by following these steps (Menu -> Invest -> shown as “Buying Power” under Market Value). Both ‘Net Unsettled’ and ‘Cash Balance’ are included in the ‘buying power’, so you can only submit a withdrawal request to transfer funds in ‘Cash Balance’.

Please note that if you execute more trades within the (T+3) period after you make the first sell trade, there may be additional settling time.