This sounds excessive but our top three clear coats all have very fast dry times which will cut down on the time to finish your project.
Top coat for latex painted cabinets.
To give painted furniture maximum protection top coat paint with 3 coats of clear coat.
For almost all dark matte paints i like to use a poly or wax as well.
Do not apply water based polyurethane over the top of gloss latex and acrylic enamel.
Your best bet would be painting them with an oil based paint as the top finish paint as well.
Polyurethane is a clear varnish that dries to a hard solid finish.
For high traffic pieces any table top kitchen cabinets kids furniture i definitely recommend a top coat to provide the best protection to your painted furniture.
On the other hand a few fresh coats of paint can go a long way toward transforming your existing cabinets for a fraction of that price.
I think you would want to try and sand off that latex paint give it one coat of the primer and then come back with your color in an oil based paint.
It protects your wooden surfaces from scratches and prevents paint from peeling and.
How to use polyurethane over latex paint.
This will give your piece maximum hardness and durability.
If you painted your cabinets with any of these paints apply a water based poly over the top to prolong the life of the finish.
Polycrylic might help but probably not for long.