Did you monitor your GPU temperature before that including hot spot?
Most probably it was overheating due old thermal paste/pads. Just cleaning dust may not be enough for old GPUs. Last year I repasted my old MSI RTX 2080 bought in 2018 and it dropped temps by about 15-20 degrees.
No GPU should die from continuous 100% workload (unless it overclocked that can cause early degradation) if it being maintained properly and has no hardware defects.
DT is demanding and sometimes can use 100% of 20 series GPU.