To successfully paint a concrete slab on grade, there must be a vapor barrier under there to stop moisture vapor transmission.
Think of concrete as a big, thick sponge. Lots of nooks and crannies and capillaries that lets moisture travel up and down.
If you cover the concrete with coating, moisture vapor transmission will eventually make it pop off. That's why all these guys are saying don't do it or you'll always to it. It will look great for a few weeks, or even months, and then it starts. Pops off just enough to make it look shitty and puss you off. So then you pressure wash it, scrape it, and do it again... and again... and again.
That's why basements and garages get the 6 mil plastic down before the slab is poured... to stop the moisture vapor from coming through the slab.
You could try a thin concrete stain that soaks in a bit and won't chip off.