It seems far more likely to me that its an unimaginably complex mix of both. I mean, afterall, the experiential 'reality' we experience daily is both a part of the 'outter world' and a product of our minds....Moreso a product of our minds if you ask me, since what physics is telling us is is that the outer world doesn't look diddily squat like how we all see and experience it

But even if only the former is true, and we're not contacting other dimensions/aliens/entities/intelligences/deeper layers/whatever, the implications of the experience as it is are still extremely profound

Again, i have to ask, what makes you think it would have to be either or? Hyperspace is a mystery inside a condundrum wrapped in a riddle dripping with paradox

I've encountered entities that certainly seem like reflections of my own mind in some bizzarro hyperdimensional way, and others that seem utterly alien and have nothing to do with 'me', and still others that are a mix of both, and everything in between. Its not so simple as either/or in my opinion