I went through something scary today

Yeah, there is no authentication for phones anyone can claim to be any number and appear to be. If you get a call off anyone. You must call them back (on the number on your card in this case) to ensure they are real.

I'm not suggesting that these people can't be very convincing. They can be and they are. But even if you weren't immediately suspicious of the bank ringing you, I'm wondering how it didn't set off all the alarm bells in your head when the guy suggested that you needed to move your money into a crypto account to keep it safe. And through a third party app that isn't connected to the bank at all? To my mind this should have screamed scam from a very early stage. At the same time, obviously for whatever reason it didn't, and it's worthwhile making the thread if even a handful of people read it and wouldn't notice it was a scam in the same sort of situation. I understand feeling bad about this because you really shouldn't have been pulled along by it, but at the same time no harm was done thanks to the actual fraud prevention systems doing their job and blocking the transactions, so this is something you can (and surely will) learn from.

The scariest part is the scammer managed to fake his number to be the same as one of HSBC payment fraud team's phone numbers to convince you about their scam

I don't know why in 2023 phones still don't have authentication lol. I'm into cyber security, as a prank sometimes I like to call a freind and spoof their number so it looks like they're getting called from themselves, it's surprising how easy it is

REALLY BE CAREFUL - YOUR BANK WILL NEVER CALL YOU SUDDENLY TO ASK YOU FOR ACCOUNT DETAILS OR A TRANSFER

I feel like this is something that almost everyone in this day and age, except for perhaps extremely elderly people, is already aware of.
I'm surprised you were taken in by it, to be honest. But anyway, let that be a lesson learned now.

Sounds like you had a lucky escape and great that you are warning us too. When you say he manage to say a lot of details, what do you mean? Is it your personal info that he go from somewhere?

He brought up my (later cancelled) card number and account number etc. He spoke very professionally, ironically preaching account security while (probably having) hacked my account. That's why I felt he was really an HSBC manager.

I changed all the passwords after this incident as well and have so far not received any SMS from HSBC warning me of any unauthorised login. I hope everything would be fine.

oh so he knew your account and card details already?

He won't be able to do anything since transactions require OTP/in-app approval. And if anything suspicious shows up, I can simply call the bank and police (again) as advised by HSBC staff. I believe it is insured.