I am WFH now too. I typically workout in the morning and would switch to an employer polo shirt. Then we lost AC.
I started staying in my workout clothes just because of the lack of AC. And I never went back. I do keep a jacket if I HAVE to show my face.
I prefer workout clothes because I walk for my lunch break and then I can slip on shoes and go. If I have any obstacles like changing clothes I may change my mind about walking in the heat.
We have sidewalks and a nearby park so I can get in a good walk. I am going to indulge myself one day and get on the swings and play equipment.