This is how it happens normally in non-covid world. There is no reason you should fire everyone publicly by the CEO, likely someone the employee never interacts with. The person also needs to know the next steps, for instance if they'll get paid of for vacation days, how to sign up for Cobra (if in the US), etc. You can cut off access prior to notice. Ideally they would all be done within a short period.

I've been around when a firm did a mass layoff. It's unpleasant and of course there are rumors and of course people are offended, but this is the correct way to handle it.