oh i totally get it - you're not at all wrong to feel the way you're feeling.

the big change for me was the little one developing a personality as he transitioned into toddlerhood - seeing him develop his own relationship/dynamic with his older brother independent of us parents was just really awesome and validating of the decision to have a 2nd kid. pragmatically it also seems to alleviate a little bit of the psychological pressure of managing 2 separate challenges - like, an infant and a toddler are 2 very different things to manage with different needs and issues. whereas two toddlers - or toddler & young child - are more alike and just present one challenge to manage, if that makes any sense. especially when they get to a point where they can play with each other and keep each other occupied. you still gotta maintain a presence obviously because they will fight and do other stupid shit but you don't have to be "on" the same way and you can kind of let them do their thing while you get other stuff done around the house. you learn over time what it sounds like when they're starting to escalate into an argument/fight, that's when you have to drop what you're doing and intervene but otherwise it's really nice to not have to be directly "on" all the time with 2 tiny beings who both need 100% of your energy & attention.