Hot take: the Great Filter is the fact that we're actually alone as an intelligent species in the universe.
Occam's Razor and all that.
Occam's Razor and all that.
Anything else is, alas, wishful thinking.
Other stars are a long ways away, and intelligence-generated signals mostly dissipate into the cube of that distance. Also, the vast majority of stars are far enough away that intelligent life would have had to evolve a lot sooner in order for the light to have already reached us. Occam's Razor is going to look at those before working out the more complicated questions of how common life and intelligence actually are.
It is unique by definition, because we happen to live on it. There is no need to reason or explain anything, because it is a simple fact.
There is absolutely no evidence that there are "ample opportunities" for aliens to exist. Default assumption is that there aren't.
The question however is unknowable: the speed of light compared to the size of the universe is just too slow. We have every reason to believe most intelligent species will rise, develop, and die off (as their star dies!) and we never find out about them - either the signals never reach us before our star dies, or they have already passed us by.
There is more to the universe than what we can observe, our light cone is a fraction of the expected higher bound, assuming a finite universe.
We are also one of the first generation of planets with heavy elements - decreasing the odds of a species originating before us.
But the universe will be around for a long, long time;
Far, far longer than it has so far. We may be the first, but to assume a filter at this point is an anthropomorphic bias so ingrained it's nearly impossible to cognitively self-reflect on.