if he lied about monaka being the strongest opponent he's faced then it's safe to say he lied about using 10% of his power plus we can't scale god level powers so it's hard to say how much he was even using in the beginningHe literally states it bro.
If that was the case then both vegeta and goku would have already surpassed Beerus post T.O.P with their god powers
There isn't any reason for him to lie here.
yes exactly that proves he didn't use 10% he used less of itIf it only applies to the level that Beerus used to knock out Vegeta, then not necessarily.