Do most SWAT agencies use JHP (hollow point) rounds, or standard ball point ammo for their submachine guns?

Both. SWAT teams equip themselves with specific rounds, depending on the environment they’re operating in. For instance, if they’re serving a warrant in an apartment complex, odds are they’ll be using a softer slugged round, so if they do need to open fire, there’s less risk of bullets spraying through the sheetrock/plywood and into other apartments. If they have intel that suggests the suspect is barricaded in a home with brick walls or cinderblock, they may also use a softer slug to decrease ricochet in the close quarters. Conversely, for a suspect who may be wearing body armor, you can almost guarantee they’ll be using hard points, or armor piercing.
SWAT, SRT, or ESU (as we call them in NY) have any array of ammo at their disposal, there’s no one standard type.
I’m not in law-enforcement, but I’ve done lots of research into law enforcement for some things I was writing.