I live in a pretty hot climate, but it’s only really unbearable at times due to shoddy building and bad urban planning. Even then, summer can be difficult.
I can’t imagine what it’s like on the equator, especially in dense urban centres. What’s Mumbai, Bangkok, or Singapore like at the height of the wet season?! How do millions of people function day to day?
I’m about to move further from the equator partially for this reason.
If you can, swim 2-3 times per day, or at least a quick cold shower.
At night it is at least a little more pleasant to be outdoors due to the sun not beating down and you’ll feel better for getting out and doing something.
Also seek out indoor spaces with aircon or green spaces with shade that are much more pleasant, if you can.
If you have to do manual work outdoors then god help you.
But you do get a little more used to it over time, but very high temps are always unpleasant.