I think Wednesday off with Monday (or Friday) as the non-nursery day is perfect.
I found Wednesday a great day to have off, as I had two intense bursts of activity on my working days, with a day off in between. I had a few friends with the same day off, and really made the most of that day.
Monday is a good day to have off nursery, due to Bank holidays. So your plan is perfect.
I had Wednesday off for years, and DH also worked 4 days with Monday off, and it was great.
At the start of the first lockdown we switched to working 5 shorter days to cover childcare when schools and nursery closed, and we have fallen into keeping that pattern. It has advantages now the kids are a bit older. But I really miss my Wednesday off, and might switch back at some point to make the most of the last year before my youngest starts school.
The only downside is that I do end up spending lots of half days off on Xmas concerts, sports days, bring your parent to nursery day, etc, which are always Fridays. Also, the local toddlers group was a Friday - some people hate them, but they are a lifeline for many.