I don’t know much about White Mage since it’s not at 70 but in terms of healer balance overall I definitely think Scholar can do too much too easily. There can’t really be a place for White Mage when Scholars are pretty much guaranteed a slot in content where you can choose your party.
Astrologian is fine in that it can do it’s job as a healer, dps, and buff the party(cards). Scholar can pump out ridiculous healing alone, high dps, buff the party, shield to the point of negating certain mechanics, all while the fairy uses the strongest Regen ability in the game (afaik) for no MP cost.
White Mage can...heal...that’s it. It can deal damage, yeah, but that’s nothing special in FFXIV