This is something everyone does in varying degree and does not necessarily mean you have ADHD.

Looking at this behaviour in isolation says nothing WRT whether or not you have ADHD…so the answer is maybe, maybe not.

Only seeding new stuff that everyone else is also seeding is not good for torrenting in general, it will kill a lot of content that’s more than a few years old and/or not completely mainstream.

Can’t have 20+ tb in a seedbox at a reasonable price