Yes-- I’ve actually read this study. I’d draw a distinction between derealization and anhedonia and would further note that is a tenuous link to subjectively think of drugs that seem to catalyze some nebulous feeling of disassociation. In my personal experience, perceptual derealization was a strong component of my symptoms (related to disinhibition of GABAergic relay neurons in the reticular formation), but I have not experienced typical anhedonia. As you’re aware, we all have comparatively different manifestations of symptoms.
The case of NMDA antagonism is a complicated one as these glutamate-activation ion channels are necessary for proper neuronal functioning but can induce toxicity when over-activated. On one hand, depressed conductance of Calcium ions can be beneficial in reducing neuronal hyper-excitability, but on the other, Calcium ions and CaMKii are necessary signal transducers and phosphorylators for maintaining cell surface expression of GABA(a) extrasynaptic receptors.
In my view, Mg supplementation may confer some of the benefits of NMDA receptor antagonists as it is a competitive channel blocker at physiological conditions that is displaced when glutamate binding affinity rises, but even this is problematic as Mg is necessary for cAMP by adenylyl cyclase (which foments excitability through secondary signal transduction). Here is a recent, great study that on that: https://www.nature.com/articles/s41598-019-53087-4
Unfortunately I think you’re largely barking up the wrong tree with a focus on NMDA receptor, though reducing general neuronal excitability could be a benefit to many of us.