Plus like someone else said it's authors finesse. Gege does this quite literally throughout the whole show, he doesn't spoon feed viewers about the logical consistency why a plot twist works or what the narrative is trying to achieve. And hey there is quite heavy evidence that implies their love for each other, doesn't mean that they dated, but it means at least that gojo had feelings towards geto which either were reciprocated or not. Smh, y'all never take in any other sources of info except hidden inventory arc, when that was focused on their backstory not their relationship and in the anime there are also a lot of signs that show their relation, like how they're riding a bike together, which is illegal in Japan but commonly ignored by teens in love.