How to cook in olive oil
It sounds like you feel that 350 is too low a temperature to effectively cook fish and some other foods.

In fact many of the foods that people saute in olive oil are vegetables which could also be cooked just fine on top of the stove immersed in water. By that method, the vegetables would not exceed 212°F, since the temperature of water can't go above its boiling point. You may decide this isn't the tastiest way to prepare vegetables, but they would certainly cook and become "done" at that temperature.

Likewise for fish and other meats, as I look up the internal temperature required for "done-ness" on this site and other internet locations like kitchn, etc., various meats are considered done when their temperature reaches a level somewhere between 145°F for fish, and up to 170°F or so that someone recommends for well done beef. 

So it shouldn't be necessary to exceed olive-oil temperatures in order to get most foods to cook. It might be puzzling that sometimes you do use much higher temperatures than that in cooking, like in the oven. But the food itself doesn't get as hot as the oven setting. 

When you preheat your oven to a nice hot temperature (above 350), and put in some raw food to bake, it takes a while for the hot air in the oven to bring the food up to a fully done temperature, since hot air doesn't transfer heat very efficiently. However the food won't reach an internal temperature the same as your oven setting before burning. It will be done before its temp. gets that high.

On top of the stove, olive oil in a pan transfers heat to the surface of your fish, vegetables, or chicken etc. faster than the air in the oven. But either way will successfully get the temperature of the food up to the level of doneness, and well below the smoke-point of olive oil.