Brian Gaff brought next idea :
Here it was outside 38 c inside 26c. Still too hot and definitely too humid
yesterday. The issue was of course that if you sweat in a humid environment
where the air is already saturated, it does not work to cool you down.

I minimised clothing, got out the big fans and used a hand spray filled
with water on the two dogs. I took three showers cool during the course
of the day and rather than drying off, allowed the water to evaporate.
My final shower was to go to bed still wet.

To help cool the house, I added a large fan on the bedroom window sill,
in front of the open window. Had it got much hotter, I would have
broken my rule and been hanging wet sheets in front of a fan, to form
an evaporative cooler.

My rule is no wet washing hung to dry in the house, except in the
utility with the fan and dehumidifier running.