How should I prepare to plaster my brick fireplace?

I have a kind of ugly (okay, eye of the beholder) brick fireplace that takes up half my living room. I’d like to plaster over it. Or skim coat it, or stucco … something. I just want a better finish than simply painting it. A plaster/stucco looking finish.

I’ve cleaned it pretty well though there’s definitely some soot stain still.

We don’t use the fireplace, but I’m assuming one day someone else will want to so I don’t want to ruin it or render it unusable.

Here’s what it looks like now:

My thinking is to cover just the red brick, not the interior.

I’m reasonably competent with home improvement in general, but I have no idea what I’m getting into here. What should I know before I had to the hardware store? (Or call them and ask them to assemble a box for curbside pickup, since we’re on COVID-19 lock down in CA)