Can I wash the hot pan, just removed from hob, or I need to wait until it cools down?

It’s better to wait while the pan cools a little bit down and becomes warm. Otherwise it will suffer from termal stress, which can shorten its lifetime.

What heat level should be attained and maintained while cooking?

Generally food is cooked at a temperature up to 170⁰С.

There is such a thing as a burn temperature of nutrition products.

Every product has its own value of this quantity. The peak value belongs to oil.

The smoke point of oil is 220⁰С. Other products are generally cooked at lower temperatures.

The heavier and thicker the pan is, the lower its heat maximum and the more “accurate” and delicious the cooked dish will be.