Get some sun/solar sleeves. With the wind created on a bike and the fact they block the sun I find them cooler than riding in short sleeves.
Get a bucket hat/wide brimmed hat (my personal choice at the moment) For golf… bit harder when riding a bike…
put sunblock on your hands and face
wear sunglasses
If you aren’t doing anything requiring lots of exertion/stretching wear pants. They make some really light weight pants these days.
I burn like its my job and have had no issues since getting smarter about what I wear going outside.