So how powerful is Rerir on the powerscaling level of things?

Right now he's at 10% of his peak power. The character say he's going to "get stronger", but but he's not collecting his missing pieces anymore, and he no longer has a heart. Say he's capped out at 10%, who can beat him?

Could Varka, who's talking to him, beat him? Could Capitano, the 1st Harbinger? Could Arlecchino, the 4th Harbinger? Could an Archon (Zhongli, Raiden, Mavuika) beat him? Could Neuvillette beat him?

How powerful is 10% of peak Rerir?