> You will need to buy, at least, a bunch of decent 120mm fans to prevent this or invest in some water cooling

There's a cottage industry of 3D-printed fan-shrouds for data center GPUs - 120mm are often the sweet spot for quietness and practicality. The shoud smugly fits the GPUs intake, so it gets all the airflow from the attached fan(s), whose speed curves can be attached to GPU temperature.