What, exactly? AWS is legendary for maintaining compatibility. Steve Yegge's article gives a good break down on how infamous GCP's deprecation practices are.
I was lucky in that GCP killed off the feature I wanted before I ever used it, so I didn't have to get burned in production. AWS has never burned me. (GCP used to have a service to do transformations on images in object storage, which I learned about in an App Engine book. It took me a few hours of searching to even find the deprecation notice. Now I just use https://github.com/awslabs/serverless-image-handler because I don't trust GCP).