There's no reason to assume that the scaling doesn't hold up because it's been a long time. By that argument I guess claims and feats in Part 1 Naruto are irrelevant now that Boruto is around.
I never said that. What I said is that his Normal Punch's didn't cause damage to Boros that'd even be instantly lethal for humans, but did cause damage to Orochi that would be instant death for humans, and he barely survived via type 2 and regen.
Yeah, he also let Orochi use his strongest attack and was unphased by it. Saitama not trying against Boros doesn't mean he wasn't impressed by him. He tried to kill him with his first punch, it failed, surprising Saitama. He then commented that Released Boros is strong after taking off one of his arms with another hit. When Boros goes on a rant, Saitama cuts him off, asking if he's already done showing his moves, prepared to finish the fight if so. Boros keeps going, Meteoric Burst surprising Saitama, before kicking him to the moon, where Saitama comments that it's almost like a real fight, or is close to looking like one in the Vib translation (which could be interpreted the same way). Saitama then comes back down, hits Boros again, cuts him off and uses Consecutive Normal Punches, then uses Serious Punch to cancel out CSRC. Afterwards, Saitama yet again claims Boros really is strong, before walking away, shadows over his eyes, in sorrow. When regrouping with Genos, he once again says that Boros was strong. And when he fights Orochi...he doesn't acknowledge him as an opponent, a Monster, or anything worth even attacking. He humiliates Orochi, makes no comments about his strength, and one-shots him before moving on without a second glance.
Neither was a problem for Saitama, they were both far below him. But unlike Orochi, Boros stood out among everything else as someone truly powerful.
Saitama had no reason to think Gaia Cannon was his strongest attack, I don't really understand that argument, and he clearly wouldn't have lasted long otherwise seeing as Saitama blitz's and one-shots him.
No, and I don't see how that's relevant, because Orochi isn't even 5-B.