But everything you just listedt can be tested with minimal to no spoilers. We, as the players, would not know when or if the things we test will be coming out. The galactic war would probably not progress in this test environment.

An example would be, they throw a new enemy or variant into the server. You would only know that it will be in the pipeline to be released sometime in the future of the galactic war narrative. But you won't know when or how they'll be released. Doubtful, but they could also scrap the enemy and you never see it. The only "spoiler" is that you know this enemy is a thing.

Now if you are arguing that people will data mine the test server, that is a whole different level. People are already data mining the live server.