I remember this phase. It felt so wrong to be focusing on feeding baby when toddler needed me, and of course toddler needed me whenever baby needed feeding.
Youre so very, very conscious that you've upended their world, you can see them struggling, you literally miss your toddler with every fibre of your being. I found it a really hard adjustment.
But.
Child 1 needs to learn that Child 2's needs matter as much as their own. They need to adjust to being part of a family, not an only sibling. I honestly think its best for them to ride out this adjustment period just like you have to. Sometimes Child 1's needs come first. Sometimes Child 2's do. Child 2 must be fed, then I will play, snuggle. Mummy still has enough love for everyone. They'll get it, and their lives will be richer for it.
I found Siblings Without Rivalry really helpful through this phase. It helped me never blame the baby for everything.
The challenge of how to spread your time from now on is your no.1 challenge.
If you want to quit bf because you dont enjoy it, of course do. But I dont think you should quit to enable more time and attention for Child 1. Its best they learn they have a sibling whos needs are as important as their own, but mummy loves both, asap.