The incredible amount of investment by the Chargers into their offense. Rebuilt OL, Joe Alt, Rashawn Slater, Zion Johnson, two 1st round receivers in Ladd McConkey and Quentin Johnston, a burner in Palmer, big FA signing at RB in Dobbins, a stud QB in Herbert: basically everything you want in an offense, with immense amount of resources expended.'
And you got your butt kicked by a much superior defense.
Football is a funny game, and I absolutely do not buy this narrative about offense.
And before you tell me it was the Houston offense (which is a decent offense), look at what the defense did!