GB wrote

Just a minor warning: I had an extension lead on my desktop, in a sunny
position. I've just thrown it out, as the plastic has crumbled away.
Potentially very dangerous, as the conductors were showing.

I've got a long extension lead powering the medion wifi repeater that
is half way down the back neighbours back yard, providing free wifi
for that neighbour. The extension lead runs along the top of the fence
rail in full sun and it has lasted fine for years now, no plastic rot at
all.

I've got others inside the house that have the full sun on them
right thru the winter and those have lasted for decades literally.

Yours must have been cheap crap extension leads.