No, it's not fair. It's really, really not fucking fair.
And the people who coo "Well he's the one who's really losing out isn't he, never getting to see his kids grow up?" can fucking do one too. These men don't care, that's the point.
(Sorry, no useful advice OP. I'm up against it too, albeit I only have two, and my exhaustion is probably more manageable, being only down to autism/ perimenopause).
Oh, I do have some advice. As much childcare as you can physically book, hopefully subsidised by UC/ TC.
And learn to close your ears to any demands primary school makes of you that aren't 100% essential. Homework, PTA, world book days, meaningless last minute charity days- they can all get in the bin.
But no, nobody cares. Nobody motherfucking cares or will lift a hand to save you from drowning. You have to resolve to survive just to spite them.