I agree that he would probably still be high needs even if you switched to formula and bottles. You would just have the extra hassle of washing bottles and buying formula.
My DD is high needs too. I have a 22 month old son and I deal with the same guilt of not spending enough one on one time with him. It's really really hard. It's the hardest thing. No one who isn't going through it will ever understand how hard it is to feel like you have to choose between which child to spend time with. Trust me I get it. I'm still trying to get DD to take a bottle too, the problem is I don't ever have time to pump
What type of bottles have you tried? DD won't take the ones DS liked so we've been playing a mean game of find that nipple that she'll take.
Ok I'm not a big advocate of CIO or intentionally torturing our children, but my Peditrician told me that babies will hold out and fuss for hours on end on taking a bottle when they want mama. However, eventually they do take the bottle. Maybe you can get someone who knows it will be hard and just go have a date with your older son. Be gone for a few hours, maybe 1/2 a day and reconnect with your son while your DH or mom or MIL stays with the baby and tries to get him to take a bottle. It will be a rough day at home but might be helpful in the long run.
Try to hang tough a little while longer mama. Because honestly, how would you feel if you stopped BFing and nothing changed? You'd still have a high needs baby who only wants you, you'd just be giving him inferior food.