You can get a pretty good finish with a roller BUT it sounds like you are expecting too much.
You will never get it smooth like a car unless you spray. NEVER.
You could sand that thing into a pile of dust before you get rid of the 'stipple' a roller will leave.
And Black is the worst colour for this.
If you want a near perfect result, go buy or hire a compressor and a gun and you could paint it in 1 day from start to finish. And before some of you say BS, Dulon or acrylic car paint dries in minutes and actually requires you to put on the next coat while the last coat is still fresh.
I cut down a full size cabinet for my nephew.
I sanded the old brown sides, filled in some imperfections, sanded the filler, primed, sanded, primed, sanded, painted 3 finish coats left over from spaying my car and buffed it til PERFECT all in 1 morning. To apply 1 full coat on the whole cabinet was about 2 minutes max.

You can see the original laminate woodgrain effect through the paint which gives you an indication of how thin it goes on and how darn good it looks.
Now if you want to stick to the roller, you are going to have to accept that it takes time and you are going to have to live with slight stipple and brush marks in the corners.
Up to you mate.