Are 60C heat waves predicted by 5C of global heating? (The worst consequence of global heating)
Neither an answer, just common sense.

Not sure if anybody can give exact numbers for temperatures of future heat waves in their projections. Predictions are difficult, especially those regarding the future. But there is consensus and now observation that heatwaves become more frequent and hotter not only on land. One could perform a search for publications that deal with the impact of land heatwaves, e.g. on agriculture (wheat for example), desertification, loss of habitable space, flooding, loss of resources like potable water, etc. There is a lot of published work around.

We went past the 1°C warming compared to pre industrial levels in 2015, after [https://www.ncdc.noaa.gov/cag/global/time-series] and many publications. Current estimations range between 0.9 and 1.6°C for 2019. Several islands have been devastated in the past years, damage still not totally repaired. Jakarta is drowning, catastrophic fires in California, Australia and elsewhere, fed by drought, heat and mismanagement, cost lives and property.

The effect of past and current heatwaves on the health of the population is pretty well visible, western European countrie's and the US health departments have published their estimations of fatalities attributed to heat.