My criteria for the difference between a consoomer and a collector are as follows:
1. Wasteful: the person buys more than they could feasibly ever use
2. Mindless: there is little to no engagement required
3. Bland: there is no meaningful difference between experiences or items
4. Compulsive: despite requiring little to nothing of the persons time or energy it some how it takes up all of it
5. Trivial: no matter how you slice it the thing isn't important
6. Pursuit: the finding and purchasing of the item is more important than the actual act of possessing the item
If a "collector" meets 5/6 of these criteria I consider them a consoomer. Furthermore: Consoomers seem to fall into two major "subsets", those who consume for the dopamine hit that consooming gives them, and those who wish to buy into a group, in this second case the act of consooming grants them status within the group.
Edit to add:
I think the difference between enthusiast and consoomer is a gradient rather than a distinct line, but it's somewhere around buying a lot of stuff just to have it. There's nothing wrong with liking things and living in a house with no decorations or personal touches would be a bit grim, but when you start buying a lot of the same or related things purely to accumulate them, you're getting into consoomer tendencies. You can descend into consoomerism like an alcoholic descends into chemical dependency. Someone can start out really loving music and buying physical copies of albums they enjoy, then they start buying a few special editions, then albums they don't love to have complete discographies, then new releases just because they're hyped up and sought after and throw tantrums if they don't get one, and then overpaying for multiple presses from different years or labels where the only discernible differences are the matrix codes. I'd say the change is somewhere around step three, where they're gone beyond what they originally loved and are buying things for their own sake. For example, buying an action figure and even a couple of classic toys that you've always admired isn't really consoomerism, but collecting anything with the logo on it is in that territory.