With open models this isn't as true. The weights are local, you bring your own compute, there's nothing between you and the model. Regarding what is a better result, personally I encourage you to define what a better result is in an evalset and then optimize against that. Agree that having no criteria is not a great situation to be in.

This was the main point in a tutorial I did about a month ago now showing how to make a simple AI app using gemma, though the principles hold for any LLM.

https://www.youtube.com/live/9zM_93mYdu8

Hope this helps!