single stage vs base coat clear

In a different, earlier life, I was a full-time painter.
Doesn't mean I know jack about today's finishes.
That said almost all I ever did was single stage acrylic or polyurethane enamel.
They all looked good, and held up quite well.
Typically they were neither sanded or buffed, so you had better do a good job with the gun.
You can buff the metallics, but you can't cut them too far, otherwise spotty uneven color.
You're not going to cure bad orange peel in them,only reduce it. Solid colors are more forgiving.
Nothing wrong with single stage at all.