@chillcwill Do it! I think it would be a detriment to your eldest to pull them out for 9 months before they're due to start School.
Also, dropping off / picking up 3 kids from daycare sounds a lot easier than taking care of 3 kids all day. Having to load them all up by yourself to get them out and about. And it will be even harder because you will be exhausted from a newborn. The middle will probably enjoy at first but then might struggle with not getting enough from you and will struggle when you eventually send them back to daycare.
Your eldest should be fairly self sufficient by the time baby is in daycare, they should be able to get out of the carseat, grab their bags etc, walk without needing to hold hands. Our eldest is almost 4 and really doesn't need much help. The middle will not need much, help them out of the car and have them stand with eldest whilst you get the baby out. On the way home open the door for the middle so they can climb in, then put the baby in fully strapped, come back to strap in the middle. Drop the baby off first/pick them up last so you don't have to lug them between classrooms. On occasion you may need help with the middle who doesn't want to walk/go to class, in that rare instance have a staff member assist with the baby whilst you man handle the middle. You can always go back to the baby after you drop off the middle to make sure teachers have/know everything they need for the day.
Having a plan in mind for how to tackle these will make it easier, if it's a struggle, do a debrief and figure out a change in strategy.
Your career would do better to not take a long break, your eldest would do better to not take a long break, your income would be the same regardless (working and paying all to daycare, not working but no income), and your brain will probably appreciate not being needed and demanded by 3 kiddos all day.
