Dh does want to step down his career but I suppose I am a bit sceptical as to whether that would actually translate into him doing more childcare such that we wouldn’t need a nanny. I think he has a rosy idea of what stepping down your career looks like which probably wouldn’t be born out in reality.
That's what I was thinking. There used to be a daytime TV show where they sent mums, mainly SAHMs to a spa with a video to watch the dad cope.
All the dads had plans for grand things that didn't work out, one that stuck in my mind was the dad taking his child round the supermarket on his birthday, the child wanted a particular cake but dad was going to make one - you can probably imagine that the child ended up with no cake.
It seems to me that you enjoy your job more than your DH does so it would make sense for him to take over some childcare, can he drop to 4 days?
I also think you are right about shorter holidays, plan three a year, one for you, one for DH and one for the children.
Obviously one or both of you have to be there for the children (unless they want to do a children's holiday when old enough) but your individual holidays could be solo or as a pair.
As for Christmas. I don't do it. I buy two presents and that's it. I'm usually solo, except for one year when I sat with my carer and we watched a marathon of 'make over home edition' and cried at every one.
Scale it back, there is no reason for you to host, and I bet it is you who hosts.
You don't need everything.
I think Christmas is like living in North Korea, everyone pretending to be happy, all the music is about the great leader and how wonderful things are, eating food you may not actually like, spending money on things you may not use, having to have certain people to visit.
Write down what you love about Christmas and dump the rest.