Honestly, Pearl's betrayal annoyed me more than Kira's. I was surprised to find so much hate for Kira and not for Pearl when I came here, to be honest.
Kira's resulted in frankly a minor delay at worst. Pearl's could have feasibly resulted in the chalice vanishing to some completely unknown spot on the planet if someone in Looter's Bay had used it, essentially permanently dooming Eliza to not being healed. Unless Lucid can tell where it is and point us in the right direction, which feels like a big "if".
Pearl definitely had her reasons, and I forgave both Kira and Pearl fairly quickly, especially since they both expressed remorse. But in the moment, Pearl's was definitely more aggravating to me, especially since we'd known each other far longer by that point than when Kira had her betrayal.
Also, Kira can be pretty cute on her path when she lets herself be vulnerable with you. Probably also helps that I have a thing for redheads...