yup. the killer here comes when the low temp doesn’t go below 100f - heat simply builds higher and higher and there’s no respite; this causes hvac systems to begin to struggle and power systems to collapse as infrastructure like transformers blow (expensive and slow to replace, with low production rates to boot) or transmission lines to sag under the heat x the transmission loads, often causing wildfires.

have been to places like death valley and central texas near Killeen - once it was 110+ for an entire week, highs reaching 117f! and at night it wouldn’t get below 100.

It’s like breathing burning air, it’s exhausting and on top of all of this, people aren’t made to work in these kinds of conditions and as temps rise, will asphyxiate as their lungs struggle to pull oxygen out of humid hot air while their core temps climb, unable to dump the heat through respiration or perspiration.

https://www.sciencealert.com/scientists-identify-the-maximum-heat-limit-the-human-body-can-take

If the humidity really were a 100%, the dew point was at 36° and water was condensing on your clothes. With a relatve humidity of 100% the Wet-bulb temperature is the same value and thus well above the level where sustained exposure (multiple hours) is lethal even to young and healthy people. Wikipedia lists only three instances where such conditions have been measured (so far).