I think you've got the ideal setup there. 5 days a week in the office leads to too many distractions / meetings; but 5 days a week WFH leads to loneliness. I'm currently stuck only allowed to WFH when absolutely necessary. I'd love to sell this to my employer - was this a change that got implemented or was it that way from the start?
From the start because I could not afford to commute, but I am also a cofounder so I have a lot to say on the issue. I think that for just plain "time to crank out massive amounts of code" nothing beats working from home. I've coded most of the non-routine new stuff like new improved libraries and frameworks this way. For coding maintenance stuff: I think I can do that better at the office.