Something that helped me personally, though it might not financially be an option for all:
For one year I did 3.5 days a week, but I proposed it as a flexible 3 or 4. That’s because 0.5 day wasn’t as helpful to the business, as knowing I could do a 4 day week when required. It meant I paid for nursery 8 days instead of 7, as I had nursery Mon-Thu so I could do 4 days in any week. I chose Fri as my non working day, because I knew in my company, that Fri was a meeting “light” day, as many were travelling home. So although I average out with 1.5 days at home a week, I never had to say, “I can’t do that date, I don’t work Thursdays”. I did work the occasional Friday too - e.g. I was requested at a week long conference, to present. It cost my household an extra day a fortnight in childcare, but it really paid dividends - most people didn’t realise I was part time that year. (lots of travelling, so not obvious not in the office!) I was promoted during that year.
More controversial, would be checking emails. I did this most days that I didn’t work, because it was easy to do so on my phone. This give and take only works if your company does give too! Mine did. Often, a single quick reply from me could move something forward, instead of waiting from Thu afternoon until Mon. As a balance - if sports days falls on a working day, my boss was fine with me working from home, and nipping up to school for an hour, no leave taken. I know a lot of companies aren’t like that... but I go back to my previous post - long before you have kids, note how your company behaves, and the culture, and actively look for a good culture. In my 20s with no interest in having kids, I heard no sarcastic comments about “part timers leaving early”.