When I'm on a company video call, the people I'm meeting with are logged into their company accounts, through the fancy company authentication system. Large warnings are displayed if there are any external participants, and I wouldn't be surprised if it's possible to disable the ability to even have guests. Third-party video conference software is banned and blocked from installation on work computers.

I am not in the finance department, but in software engineering and operations, two-party controls are everywhere. I can't check in code without reviews. I can't access production systems or make changes without approval from another team member. I would think that similar processes could be put into place for transferring tens of millions of dollars.

In other words, there are ways to deal with this that don't come down to "mistrust all technology and revert to face-to-face meetings and handing cash to each other".