Prime innovation of the interest of venture capitalists is based on a higher and better normalization of truth – upstream – than is prevalent today. Hence, if you are afraid to be copied, it is very likely because you merely have an idea consisting of a – downstream – suboptimization of an existing truth, which should not be a venture capital target and will always be subject to intense competition at the expense of profit margins.
So, if you are indeed the inventor of a better normalization upstream, it is unlikely anyone else would have developed a new normalization of truth like yours, given they are hard to come up with and thus in extremely short supply despite many false-positive imposters from subprime innovation arbitrage wallowing in the pageantry of misplaced positivity.
From a better normalization of truth upstream, it is improbable anyone else will own and develop the same consequential evolution of downstream execution that follows from it. Not in the least because an idea without execution is like a car without tires, unable to experience how the rubber meets the road of reality.
So, entrepreneurial paranoia is normal yet must be curtailed. The worst-case scenario is that your idea ignited socioeconomic value the world truly cares about. The best-case scenario is that you are the one monetizing from the excellence of its execution.
I suggest you do not confound cause and consequence, or you will fall prey to the grave depravity of reason (Nietzsche) commonly referred to as a rat-race for money that identifies anyone but a real entrepreneur. A rat-race full of cheap copy-cats that induce the very fear you referenced.