Yes I'm sure lol. Bleach characters can passively kill beings without resistance to their soul crushing Reiatsu. They don't need to activate it, whether consciously or unconsciously, it's just there and it just happens. Gojo needs to activate Infinity, although he can do it without thinking about it. It's still not passive though because it needs to be activated to work, and it still takes energy.
He doesn't. It's stated that his energy is "almost" inexhaustible. And that's both because of his amount of energy, and how he controls it. But he doesn't literally have infinite energy. Besides, if he did, he wouldn't worry about conserving it, and he does say outright that he tries to conserve his energy usage.