It kinda sounds like you may simply be a strong introvert. Nothing disordered about that. It sounds like you would prefer a stimulating conversation with one person, especially if you know them. Maybe not all the time, but sometimes is nice.

Don't get me wrong, you may have some other stuff going on as well. I'm just not sure if it's SPD =)

You could be an INTx in myers Briggs. INTPs in particular can be quirky in their own right. They like puzzles and just figuring out whatever interests them. Maybe look up some INTP profiles (there are a few and they'll give different insights).
INTPs aren't the most common personality, so we can definitely feel like the odd one out. We process information and interact with the world differently than most.

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