I myself have found from experience that high heats will not kill your plants, nor will they harm them.

When you go and look at seedsbanks strains, you will notice that there are 3 different types, outdoor indoor and greenhouse, and this relates directly to what sort of temperatures you can grow them in.

Indoor strains like to have a higher heat and 75 deg isn't that, thats too cool for an indoor strain, that is better suited for an outdoor strain.

There isn't a set right or wrong on what the temps are best at, as for every strain its different dependant on where its native too.