I think the White God and his Archangels keep those forces within reality capable of destroying reality in check, allowing reality to develop through free will, this includes gods and rogue Archangels.
He permits beings in the mortal world at the Queens power level (the mothers are too powerful), some gods (like Odin) can continue in a reduced form, other like Hades can’t really leave the NeverNever. Ferrovax is only permitted to manifest in a human form.
The Titan upon breaking this compact was dealt with by three of the White Gods champions and taken off the board.
The Outsiders are not part of this compact, but to deal with them directly the White God would have to break the compact, freeing up the gods and rogue Archangels to intervene in the mortal world again, breaking it. It is not then an issue of relative strength between Uriel and HWWB, it is a question of not fighting a war on two fronts, which mankind would be unlikely to survive. This is why Uriel is limited, he can only work indirectly through the White God’s champions, the Knights and the recipients of Soulfire like Harry. He can destroy galaxies but to do so would invite the destruction of mankind.