How do you change career in your 40s with kids and a house?

How? Im 40, two kids, mortgage and no support/family to help with childcare.

I hate my job, I hate my line of work. How do I even begin trying to change career? How do I find anything that fits around my childcare needs?

My job gives me the flexibility but I hate every day and it's taking a huge toll on my mental health and confidence. How do I make a change, I feel absolutely trapped.