Well, seen as no-one made any attempt to answer the question, I'll have a go. (Edit: Except the post above!)
Perhaps like you, I wasn't aware that in March 2020, I wouldn't ever set foot in HKG again. By the time CX finally dumped me mid-2021, the battery in my HSBC security device was dead. In addition the HKG mbl number they have on file for me is also disconnected! I haven't closed my account yet, but I did call HSBC. They said I'd need to send an (old-school) letter (with signature) to them advising you want to close your account, and advise where you want the funds deposited. My plan was to deposit it into a mates account still in HKD, and get them to transfer to me. I'm just waiting to make sure I've cleared out of the IRD's office before I send HSBC a letter.
Call them up. Send them a signed letter, telling them where you want the money deposited.