MXE has dopaminergic effects and it’s an NMDA antagonist.

Obviously this isn’t a call to chase the high or anything but if you noticed a significant improvement in depressive symptoms or your ability to do executive function-related stuff (organising yourself, staying on task, remembering things, task initiation etc.) which made life easier for you then there are other options available.

On the NMDA antagonist side of the equation, this would be where you’d find the relief in depressive symptoms, there are a range of medications that can achieve this same effect (to a lesser degree although over time it will work just fine) or there is some evidence that indicates that endogenous NMDA antagonists are surprisingly effective - Vitamin C and creatine (the workout supplement) are two cheap options which are very safe and very well researched examples of this.

On the dopamine side, this is mostly the improvements to executive function and if that’s the case then I’d recommend exploring the possibility of ADHD. There are less options available for dopamine agonists outside of the classical stimulants however there’s anecdotal reports about the supplements L-dopa, tyrosine, and brahmi being useful here.

(Obviously this stuff is complicated because depressive symptoms often have negative impacts on executive function and, conversely, poor executive function can resemble and even be a causative factor for depression so teasing out the root of the issue can be a lengthy process and it’s something which is way above my pay grade…)

If you wanted to get an all-in-one NMDA antagonist with dopaminergic effects with a very minimal side effect profile, amantadine is probably the best bet here. There’s some evidence that indicates amantadine is about as effective as methylphenidate (Ritalin) for treating ADHD. Getting your hands on amantadine might be somewhat of a tricky process although it’s pretty safe and it doesn’t have a risk of abuse or addiction - I’d either level with a prescribing doctor and tell them exactly what you’re fishing for and why or I’d play the angle that you’re looking to treat symptoms of anxiety.