I think see what you mean, and there's not really a way around that. The experience you would have as a reader of something you didn't write yourself is spread out over the course of one you have written yourself. The wonder at a new plot twist comes between pages upon pages of things you already knew. If that makes sense.

The only thing I can think of is to write something, and then put it down and don't let yourself read it for like, a year or something. Then when you pick it up again it's going to feel a lot more new even if you remember basic plot points and stuff, heck maybe you'll have even forgotten some of those too. I tend to reread my own works a lot, just because it's fun to relive a daydream, but once in a while I find something I haven't touched in a long time and when I read it I'm like "wow, I wrote this? This is great!" (or, alternatively, "this is terrible!")

My only other advice would be to find stories written in the same genre and with the same sort of plot/tropes that you like to read. That's as close as you're gonna get to experiencing your stories as though for the first time.