Well, based on the talk between Wu Heir and LDQ it's stated that there's no qualitative difference between him(Wu Heir, 100%) and someone with, for example, 99%~98%, being generous we can assume there's no qualitative difference caused by BP between Ruo and Expo Wu Heir, for example. But it's hard to believe that there's no qualitative difference between Wu Heir and Yichen that's 7 percentual points behind.
And yes, nearly all arts in PoMA are from TW Immense Dao or a parody of it. But there's more Transcendent Arts(That's, probably around this Sky-9 or even Void range) not directly given by him, for example, Wu Jian Extreme Demon Blade that's supposed to be stronger than the Wu Celestial Heavenly-Palm. Wu Jia Wind Riding Art. MG's Monkey Grab(Or his Art overall, since it's said in the Buqu fight that only the Wu Clan practices the Void/Space, and even so in a childish extend compared to what MG shows. So he must definitely created his Art; That's one of the reasons I highly believe he has Dao, for example), Delun Karmic Emperor(By his Karmic Dao), Ruo's Ultimate Sword Art(Yes, Ruo created it as a mortal)...etc.
And indeed is wrong, as said in the "Essay of Affinity" book in the library, everything in PoMA is secondary to blood, I actually think the book(PoMA) repeatedly states this by the way. Blood Purity turn the user Arts stronger, increase chances of enlightenment, Art comprehension and mastery...etc.
TW cite these and "others", so there's more people in PoMA that possess Dao(All my bets in MG).