I wear yoga pants with one of my office tops for wfh, and it looks likely that we won't be back in the office until after Xmas. For people who need to be in the office, they've commandeered people's desks so that they can spread the staff out for social distancing.
We were dress for your day already, so no real change there. I've never been in a job that required business suits and heels, even in the Civil Service. If I ever needed to be formal, I'd wear a nice dress and a jacket. I'll keep one jacket for that, and a few dresses, as I do dress up occasionally.
I do smarten up a little to nicer trousers and top when leaving the house even for shopping. I rarely wear makeup anyway, but I actually want to increase that a little, as I stopped wearing makeup due to an abusive ex. I need to practise, though, as I've not worn it for so long.
I find the work top is enough for me to feel "at work", and I'm firm in switching off at my usual time.
But having chatted to friends and family, a lot of places are relaxing their dress codes, probably permanently.