i think his “low 1C with preparation” comes from being able to consistently build stuff that can damage characters of that rating, but that doesnt mean he himself is that tier, which is why he still only has hypersonic reactions, class 5 LS and 9A striking— kinda like how captain america is 9A, but has a low 1A durability shield
obviously they would both get folded by any character on those tiers, but they have equipment that can hurt or defend against attacks from said beings, and both contexts usually involve help from the justice league or the avengers so its not like they’re out here alone (except for dumb outliers like batman dodging omega beams on his own)
maybe if someone specifies like: “batman has his super ultra mega power suit that beat and resisted attacks from the anti monitor and darkseid” or whatever tf, then i can kinda see it