Well, if I had had that information to begin with I probably would have given a fairly different response lol.
In that case, let me go into DXM's history instead. The thing about it is that it's not just some drug that was used recreationally and then somehow made it to your local pharmacy.... It was tested and marketed specifically to be an over-the-counter cough suppressant before ever being publicly available, and that's all it was before eventually being discovered as recreational. And, for that purpose, it's actually fairly effective, at least again as an over-the-counter medication, though they did make one hilarious failure when they first introduced it.... It was actually tested and approved by a government-funded program designed to find effective medicinal replacements for codeine that could not be abused. Ha!
So, in that sense, the fact that you can find a spiritual tool at a local store is just a coincidence. No one intended or expected it to be that way, and that just happens to be the place where you get it. There's nothing to try to grasp there, it just happened to work out that way. As for why it's
still available there after all these years of being more publicly recognized, there are several reasons I could think of that might contribute.... First of all, the fact that more people seem to dislike it than like it, or at the very least they like it less than most things, as a recreational drug. Second, like I said, it is effective as a medicinal drug, and obviously quite safe given that the recreational doses a hundred times higher than the medicinal doses still generally do not produce fatalities. Third, it has such a wide reputation as a "kiddie" drug just because kids happen to be able to obtain it easily that the government is probably not concerned about it really catching on. Fourth, the government probably also doesn't want to admit what a hilarious failure their design was, nor fund another study to find a replacement for it. And that's all just off the top of my head....
About all of the spiritual stuff... part of the issue is that 'spiritual' is just one of those words that means something different to everyone, and that's before you even factor in someone's ability to glean any sort of insight related to whatever they consider to be spiritual. To me personally, spiritual basically means anything related specifically to consciousness, such as emotions, thoughts, and perceptions not meant to be a reflection of the physical world (like dreams, for instance, but not the room you see around you right now), but also the concept and facets of perception itself. So, basically anything that can show me something about how any of these aspects of myself work, I would consider to give some spiritual insight. In the case of DXM, I have also had some of the delusions that you speak of, things like thinking I've discovered the truth to reality or am being hunted by "universal police" and similar things, and these are obviously nonsense beliefs that evaporate after the trip like you say, so it may seem like you can't gain much from them. However, simply experiencing them at all shows me, for example, what certain aspects of my mind do when they're either inhibited or enhanced beyond the range necessary to support ordinary consciousness, and I can use this knowledge to consider that a lesser or greater form of these different delusions always exists in my mind naturally, and therefore I should be mindful of it and watch or modify my behavior to make up for the potential faults caused by these different types of behaviors. Or, if there is nothing at fault, I can simply marvel at the inner workings of my own, and the intricate complexities of consciousness in general. Either way, it amounts to being a very insightful experience, in what I would consider a very spiritual way.
So, I can't really speak for someone who would consider spirituality to be something more religious, or any such definitions other than my own, but I can say that I personally consider DXM to be potentially spiritually insightful, if you're looking for some confirmation as to whether or not what you feel is accurate. If that is the main source of your doubt then I don't think you should need to stop using it just for that reason, but I do definitely think you should consider using it less as well if you've binged on it like that and feel that it's affected you negatively in ways. Perhaps stopping totally would be best if you feel that that is the right decision, but I can't make that call for you.
What I will say is that I personally get a lot more out of the insights I gain from psychedelics than the ones I get from dissociatives. In my admittedly somewhat limited experience with dissociatives in general, they seem to touch upon that "spiritual" space quite well but tend to return insights that are mostly just interesting rather than overly useful, not that it doesn't happen from time to time. So, I can understand wanting to pull out of it after a certain point, once you think you've seen enough of it to satisfy your curiosity in that respect, and especially if you're starting to abuse it rather than just explore.
I hope you find the insights that you seek.