Although after being Divinely Enthroned, one's strength can be significantly enhanced, such enhancement should be limited.
One especially important point is the large connection to one's original realm.
However, it is not a proportional relationship but an inverse one.
The stronger the original strength, the less obvious the enhancement; it might only increase by one or two realms, or perhaps not at all.
On the other hand, the weaker the original strength, the more obvious the enhancement. But no matter how much it is enhanced, there are limits; a low-rank cultivator remains a low-rank cultivator, it's impossible for someone who was merely in the Blood Manipulation Realm in life to be directly promoted to Immortal King after being enthroned—that would be too abnormal.
If it were really possible, Jiang Hui would definitely have awarded himself a title first.
In some ways, this is actually a form of veiled fairness.