I understand you. I also have about 25 ° C in the summer.
I watched what was happening in the engine compartment in the summer. You can even check with your hand. The engine hood is hot, the air filter housing is hot, so the engine does not get chilled air in summer and its power drops. High temperature in the engine compartment negatively affects all sensors, hoses and cables that have become damaged over time. Likewise, the engine block, without cooling from the bottom, maintains a higher temperature, which negatively affects the seals.
As for the gearbox, at a very high temperature it worked with a noticeable gear change, it jerked slightly.
The coolers cool down the fluids in the engine and gearbox, but not the accessories that work with them.
Mercedes thought about the situation. Therefore, gasoline engines and AMG versions do not have a hood under the engine. While driving, the rush of air is designed to cool the oil pan of the engine and gearbox, additionally ventilates the engine compartment and cools the intake system.