I think it's all relative, but Laser Boy seems to have it the worse. He's actively leaking out laser without his belt.

The other guys experience side effects from their quirks, which limits their use to some degree.

-Gravity Girl gets nausea.
-Kakashi gets dry eyes.
-Shoto's ice freezes himself without fire to balance it out.
-Bakugo's glands in his hands get strained from too much use.

There's the "The more I use my quirk, the more negative effects my body suffers" type of kid, then there's "I can't store up my laser without this belt, and after I shoot too much I get diarrhoea" dude where his quirk actively makes his life worse without equipment to keep it in check, let alone use it properly.