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A little water would not hurt the coils nor the injectors. Water in the fuel system could damage it.
Water in the fuel if it did pass all the filters could hurt the cylinders, but there should be a water in fuel alarm and set a code.
First thing I would do is a compression, leak down test to see the condition of the cylinders. Running the engine lean at 5200 rpm could be more damaging.
Next I would clean the entire fuel system and check for water in the filters, fuel lines etc.
Once the entire fuel system is clean I would put a fuel gauge on the engine and see if you are getting good pressure.
You say there were no codes, was the engine monitored during the test and did it meet all parameters? Your tech can also do cylinder drop tests, and injector tests. You can monitor the ignition with an inductive timing light and also do the same with each injector. If they are firing the timing light will flash.