You could theoretically stand on the core of a gas didn’t if you were superman. For a regular human, everyone a gas giant would be like falling into an ever increasing atmosphere, even if you decended slowly. the pressure and turbulence would basically crush you and tear you apart into you constituent atoms long before you reached any core. The atmoshpere on earth is like the skin of an apple, just a thin lol coating on there. The atmoshphere of a gas giant is like the meat of a peach, big thick and juicy.