I used to do 60+ hour weeks before ds.
I just can’t go that now - dh works long hours and we have no family support.
It’s true something has to give - that means either one or both of you cutting down, or more family support, or paid support, or loss of family time.
We could have continued working as we were but it would have meant hiring a nanny (3x the price of the uk here) and seeing ds only at weekends and first thing in the morning, and I didn’t want to do that.
Probably a different situation to you but work were pretty shitty to me during pregnancy and gave me a non equivalent role on my return to work. My motivation to bust a gut for them dropped somewhat after that.
I will say that 24 hr availability is very stressful.
I think you need to evaluate what can give, and what you want to keep doing. It may be possible to put some relatively minor changes in place that help a lot. Also work don’t know if it’s an issue unless you raise it - if the work is being done and you’re not complaining they aren’t getting visibility that something is wrong.
They may be shits like mine and refuse to adapt, but if your boss is decent they may not truly realise what’s going on and be eager to retain you