OK, Now I get it. I got some stand alone contactors/starters that I mounted in a homebuilt box that runs my cleaning setup

They are adjustable for current required to trip. For a breaker like what you're using, I think I'd be tempted to buy panels that just use regular breakers and gut them and mount the stuff required for the breaker, if you didn't want the box in your enclosure. Cheap & easily changed with stuff available at the local hardware store.

VFD at the same temp regardless of load: I dunno? All of mine have a high-temp, don't touch warning label on the heat sinks. I ignored and touched only to find them at ambient temp after a couple hours of operation. 3 HP drive is running a 3/4 HP motor at about half speed. Don't know what the temp would be on a larger motor running at normal speed.