According to the story above, Alex is only in contact stage with the alleged or to-be partners. What really happened, did he disclose his private details at the course of the meeting?
Nope, Alexander Choi didn't disclose anything to the scammers during the call, Alexander is somewhat experienced in the industry, so he didn't do that. I have read from a few sources about this case and this is a very sophisticated scam, i believe the scammers are exploiting some form of vulnerability in video conferencing apps/platforms.
The scammers host the meeting and forward the link to their potential victims, i think it is at that point that the scam happens. There is not so much information on what the malware is right now and what vulnerability they are exploiting. But don't keep a huge amount of assets in a hot wallet like Alex did, and if you are not the host of a meeting in any of these third party apps, then you have to be very suspicious of it, be careful, there might just be a malware lurking in there.
I feel that the best thing is to avoid talking business to strangers on the internet because most of them most be scammers. Assuming Alex didn't listen to them and ignored their request, he wouldn't have fallen for the video call which he got affected from. I ignore messages or emails from strangers.