There aren’t many things I know for sure, so, you can ‘be right’ on whatever you want, except for this:
You can only do one thing at a time.
You can never multitask. That is a myth.
You can switch your attention back and forth quickly between two tasks, such as, looking at your phone and talking to me, but you will always be missing a few seconds of one while you are looking at the other.
So, the point is, when there’s a live person, situation, or thing happening, how much of it did you see?
And if you have a project to complete, do you think it will be done faster & better if you multitask, or completely focus?