I hate the fact I can't have any original idea. Everything I want to develop is already present on play store.

Develop it anyway, as you work in it it will mutate a million times, it wont reseamble your original idea.

Find something you like, study it and make it better

There is no purely original idea. Humans have been around long enough for every possible thought to come to life. But what you can do is to build upon an existing app or try to approach the inception process by trying to solve problems.

But I can't compete with a 100k downloads app, that it's on top of the search, with my 3 users app (me, my mum & a Google bot D:) listed on bottom

Try a progressive web app
They are like apps
But you can discover them on Google search
They are pretty cool

I have this problem too, but I've decided that if I make an app that turns out to be similar to something else then at least it's a personal accomplishment and that matters more to me.

Programming experience is gained and you can make it do whatever you want.

The fun thing about this is that it’s a numbers game.

There’s barely any original IP these days.

What you have to remember is that keyword overlap is going to happen, some will install x, some will install yours.

Now, if you can make yours even a tiny bit more novel / better at it than the other one, then over time yours will become more likely to be chosen.