@moneyortime I'm 2 years ahead of you with schooling and am about to do the reverse job move. I found working FT with children in preschool a lot easier than working FT once they'd started school. They don't always want to go to wrap-around care, have activities in the evenings that start before I finish work, and there is so much more going on to mentally juggle. I am about to leave my £60K job for a £40K one that has more flexibility and can't wait!
Someone mentioned starting and then making a flexible working request. This was a route I tried, but was told not only that the job demanded my presence, but that someone on my salary should be working the FT hours, and then as many extra unpaid hours as required to get the job done. It sounds like your new role would be similar.
I also have a partner who can work flexibly, but they still have to work and can't always cover drop off or pick up. We don't have any family locally, so if the kids are sick, we have to see can rearrange their work the easiest to be able to cover childcare. Plus, once they start school their lives become a lot busier to manage, both mentally and physically - multiple daily emails from school, menus to complete, correct uniform to wash and wear, loads of in-school events to ensure they send the correct things in for so they aren't the kid in uniform on non-uniform day, or looking messy in the class photo etc. Plus more activities (that also have kit to prep for), more class birthday parties, generally wanting more of your time and attention. Not to mention that you spend all your free time trying to catch up with laundry, housework, life admin, replacing clothes they've grown out of. Unless you outsource everything with paid help, you don't get to spend your weekends with them either.
These years pass so quickly, and I want to be the one that listens to my kids reading their phonics books each evening, or sees their excitement when they come out of school and are star of the week. Sharing those moments is worth far more to me than the extra salary or pension contributions.
Good luck with your decision.