Not Everything
The idea was forming in Ryu's head even as he acted. The flaws and pitfalls of the original techniques and research notes made him realize a few things. Rather than shunning those flaws, he focused on them. While others might just see flaws, he saw areas the Martial Gods thought were important enough to try to obfuscate in the first place.
And those were precisely the weaknesses he targeted.
Ryu didn't just try to envelope his Realm Heart in Cosmos Fog, that was a waste of his time and it would drain him to an impossible extent. Instead, he chose to do something different.
The Beyond Perfect Extreme Spiritual Foundation had a profound copying and creation ability. Just to be able to take something and push it to its beyond perfect extreme necessitated such abilities.