Humans have lived during one of Earth’s colder period, but historically it’s been a lot hotter. Our bodies are well adapted for heat (so long as we can cool off using sweat)
Since 2005, wet-bulb temperature values above 95 degrees Fahrenheit [35 C] have occurred for short periods of time on nine separate occasions in a few subtropical places like Pakistan and the Persian Gulf. They also appear to be becoming more frequent.
If it’s been hotter historically, such that dinosaurs would have been totally fine with these higher temperatures that doesn’t exactly help humans...
This doesn’t seem very reassuring? For example, https://climate.nasa.gov/explore/ask-nasa-climate/3151/too-hot-to-handle-how-climate-change-may-make-some-places-too-hot-to-live/
If it’s been hotter historically, such that dinosaurs would have been totally fine with these higher temperatures that doesn’t exactly help humans...
Currently lots of the Earth is too cold to live in. In a warmer Earth those places would become habitable even as other places became too hot.