I've created a White Knight deck in MTG Arena and it works fairly well but I feel like its missing something, I just don't know what.

I'm looking to keep mana cost low as I like the faster play and I would prefer to stick purely white.
The deck list is as follows:
1 History of Benalia (DAR)
24 Plains (RIX)
1 Resplendent Angel (M19)
4 Novice Knight (M19)
4 Cavalry Drillmaster (M19)
4 Knight's Pledge (M19)
2 Valiant Knight (M19)
2 Knightly Valor (M19)
2 Ajani's Welcome (M19)
2 Moment of Triumph (RIX)
2 Tactical Advantage (ANA)
- Target Blocking or Blocked creature you control gains +2/+2 until end of turn - 1W to cast
4 Ajani's Pridemate (M19)
4 Luminous Bonds (RIX)
2 Take Vengeance (M19)
2 Seal Away (DAR)

I have played around with the idea of exchanging the Resplendent Angel for Baird, Steward of Argive.
Other cards I have considered are Serra's Gaurdian, Zetolpa Primal Dawn as I think what is missing is something big.

Suggestions are greatly appreciated. Suggestions from Mythic to common are accepted.