People gave you the exact solution to your “problem”, which isn’t actually a problem but rather the expected behavior of FSR 1.0 being implemented as a shader.
You then downvoted and complained about the user. There’s no extra advice to give: you rejected or is incapable of using the feature as designed, what else can anybody do for you?
Be careful with that, actually. Reddit mastered repeating an explanation or analogy they read on another thread or saw on YouTube, but being quite eloquent at explaining it. Problem is, if they misunderstood it to begin with, they’ll just as confidently repeat a broken version.
I didn’t notice it at first… then I started seeing explanations for things on my field and cringed at how wrong they were, and then I started noticing the pattern and the very repeated analogies on other areas too.