Yeah, in my experience the difference between 8 and 10 hour workdays were negligible (except certain times of year where I'd get to my desk before sunrise and leave well after sunset). Anything I'd do with my "extra" 2 hours per day I'd happily batch into my free Friday.
I barely see/interact with my kids on an 8 hour day. On a 10 hour day, I'd probably miss them completely.
I would like one day a week when I'm not working OR looking after the kids, however. That would be amazing. It would be great to give it a try and see how it worked out. Unfortunately my employer is a hardass and doesn't even allow work from home, let alone fewer days a week.
Young kids need 10-12 hours of sleep. 10 hours working, plus 1 hour lunch, and a 30 minute each way commute means your kids likely should literally be sleeping the whole time you're at home during a work day.
I don't know any parents that do that - literally never interact with their kids 4 days out of the week. What actually happens is parents sacrifice their kids' sleep schedule.
I do find there's a lot of benefit to flexibility though. If I'm in the zone at the end of day, and don't have anything else to do that night, I'll often work an extra ~2 hours (or until I feel like I've lost it.) But on the flip side, I will also leave early on a night where I have a lot to do outside work.
