: Is this a V+ or III+6? I see a weird chord between the iiø6/5 and the i. Is it a pun of V+ or an III+6?

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(This answer assumes that this score is a standard treble and bass clef keyboard score and that tonic is C.)

So much of tonal music is based on a set of common patterns, and one of the many reasons for studying music theory is to learn what these patterns are. These patterns become especially helpful when you look at more advanced tonal practice, because often the tricky aspects of later tonal music are just evolutions of earlier common patterns.

Returning to your example, we're left with one of two progressions: ii–III–i or ii–V–i. The ii–V–i progression occurs constantly throughout tonal music. In contrast, I can't think of a single example that uses the ii–III–i progression.

As such, analysts will prefer the ii–V–i reading because it aligns with earlier tonal practice. And as musicians get their education, they learn what these ii–V–i progressions sound like, so our brains are somewhat primed to hear this as a ii–V–i progression as opposed to a ii–III–i progression.

Furthermore, the augmented triad is exceedingly rare in tonal music. It does occur, but its most common use is as an altered V triad, and it's basically always in root position. This is another reason to be suspicious of a ii–III–i progression that includes an augmented triad on III in first inversion.

Lastly, I would argue that this isn't a V+ triad, and for at least two reasons. First is because V+ would be spelled with a D♯ instead of E♭. Second, the V+ chord really only occurs in major keys so that the raised chordal fifth moves by semitone to the third of the tonic chord. But in minor, the raised chordal fifth is enharmonic to the third of the tonic chord, which destroys the pull of the V+ chord's resolution.

As such, this E♭ is going to be best understood as either a non-chord tone (an anticipation, perhaps), a product of a larger voice-leading pattern (note the parallel sixths between the outer voices in the first two chords), or as a type of added-sixth chord.