Yeah it's kind of hard to get past the "ugh, everything has already been done" feeling. Sometimes it's worth just trying though? Although it's frustrating that there's some Undertale stuff I did before the game exploded in popularity and it was overlooked at the time, and now that Undertale is a giant force to be reckoned with, other people are doing very similar things and getting a lot of recognition for it.
I think the most rational approach to take is to just do what you want, and ignore the haters.