I've always got up a couple of hours before everyone else and pottered about in my dressing gown tidying up, washing up, doing laundry, emails, lists, supermarket delivery, checking homework, watering the garden, whatever needs doing, then change into exercise gear and workout then shower and get dressed for work.
Lockdown's been the same in that I get changed when I'm doing something different but the timetable is somewhat changed.
I now start work immediately on regaining consciousness at dawn and get a few hours in before my husband needs the office at 9am and then I do my couple of hours of essential pottering about whilst remaining contactable for work and homeschooling and supervising the children. Then I work out. Then I go back into the office while my husband is on lunch.
After that it's the afternoon and I'm just going for my shower! 
I don't like to answer the door in my skimpy workout gear so I keep my dressing gown downstairs to throw on and any delivery people who arrive in the AM will have seen me in all my un-showered be-dressing gowned glory.
Even when I do eventually get dressed it's just shorts and a vest with stretchy bra and big pants underneath.
And that's only until we've eaten dinner whereupon I do my skincare again as per Caroline Hirons instructions and put PJs on again if we're all going to settle down and watch something.
So I guess the answer OP is I don't have PJ days but the impartial observer might think I do!