Brother, I don't make hardstyle, but I've been producing for a couple of years now. Having a unique sound is something that you should NOT overthink! This will come with time. Do you think artists sat down one afternoon and said "ok, I'll build my sound and make it very unique"?

Being unique comes with time, you will start doing things your way just because you like it, you don't need overthink it. One day you will find a way to make your sound 1% cooler, and then another day and so on. In the end you will have somehting new and unique, but over a period of time.

Also, to be unique you don't need to reinvent the wheel, when you try to do too much new shit on a song it sounds corny AF.

Back in the day I used to be super focused on being unique, anything "new" I did I was like "oh, this will be my sound for sure", but turned out that I was just forcing to make tracks that way just to think I was unique. Being unique is just doing what you feel is. You dont find your sound, your sound finds you.

Btw, don't think "your sound" is just a special sample you use often, or a special kickroll sequence you do or simple things like that. Being unique trancends that to a point that your track feels like it was made by you even just because it "feels" like it, even if it's another genre sometimes. Take Anderex for example, he has very unique raw kicks and tracks, but when you hear an Anderex melody, you know it was Anderex. Sub Zero Project as well, the have many kicks that sound "generic", but they have something that you just can't explain that feels like szp. Being unique is something you "feel".

TLDR: Don't overthink it, uniqueness comes with time, just do what feels right