In a 4runner social media group I follow people are constantly posting about rust and rust protection. Some of the vehicles are just shocking to see if they are from anywhere with winter weather.
I don't know if it is better or worse on Toyota's but man o man that rust can be bad if they salt...
I certainly understand your perspective on going "OEM." I put air quotes because it is still a specialty shock made by Fox.
I wish you luck and hope it lasts.