Woaaaahhh but why would they suppress her mana? ✋

Crazy guess.
They wanted the Female Lead to be the only one with that pure power, as she is following the priest's evil intentions.
This book is backwards, the ones that should be good, are bad, the ones that should be bad, are good.

i agree it the future itll probably be revealed that the female lead in the novel is weaker than the one rn (NOT spoilers just my opinion)