I've been there with WFH during the pandemic, and being constantly interrupted by my then 3 year-old, to the point where I couldn't actually focus on anything for longer than 5 minutes. DH was in an at-home parent role and had a hard time managing her and juggling all of the other kids' needs and household stuff too. DD3 was distraught knowing that Mummy was physically present, but not emotionally present. And while some of the people I worked with were great about kids gatecrashing Teams calls, others were really awkward about it. Like, it did not occur to them that kids have different personalities, and that while some are fine with parents WFH, others take it really hard.
I've also been there with being thoroughly exhausted after my own day at work, and then having to deal with an exhausted child post-nursery pickup. The screaming in the car. The not quite knowing what's for dinner. That window where you can get them off to bed before they get overtired and wired slowly shutting. That part was hard too.
I think the best thing you and your DH can do is just talk together about what isn't working well, so that you can arrive at the right solution for you guys together.
If I was still working full time, and if DH was still in an at-home parent role, I would have gone back to the office by now. Even with the commute and traffic, that would have been the most sensible solution for us. Because that would have given me enough space, independence and transition time to keep my work-mode and family-mode better separated. It would have lowered my stress levels overall. And my youngest is always a little less distressed about Mummy not being available if I'm not in the building at all.
If returning to the office wasn't an option (like if the building lease was left to expire, or I was permanently remote in the first place), then I'd be looking at flexi time. I would either be getting up 1.5 hours earlier to get my working day finished around nursery home time, or I would take an extended break at nursery home time, engage with the kids, and then log back on for the last 1.5 hours after they go to bed.
What we ended up doing instead, was DH went back to work full-time, and I cut my hours to (in theory) be more engaged with the kids when they were home from school and nursery. I also moved on to an employer that is trying to better respect its staff's working hours and boundaries.
There are a few different solutions you guys could try. Neither of you are being unreasonable, but you have to accept what about your current setup isn't working well, and give both of your points equal weight, to arrive at a setup that will work.