Haha this is too funny! 8-Bit Music Theory's Chrono Trigger video on Non-Functional Harmony was the exact thing that piqued my interest in really learning music theory. I also know that Dolphin Shoals video well, it affected me the same way. From there I found Signals Music Studio's channel to be the most useful for me in understanding these concepts. Something about that guy's teaching style just really clicks with me. I highly recommend checking out his stuff if you're not already aware. His videos helped me finally start to understand intervals, chord progressions, and modal theory. When modes started clicking for me it's like I literally felt my consciousness expand, haha. Like I'd been made privy to the secrets of powerful magic. You can just change one note of a scale and give your composition a completely different emotional context? And you can come at that with intent and purpose instead of mucking around on the keyboard until you stumble across something that sounds like how you feel? (not that there's anything inherently wrong with that!) Amazing stuff.

I've been so busy with work and life I haven't made time to follow all your links! Instead I found myself captivated by the next big song in Deltarune Chapter 2, My Castle Town. Extremely cozy version here. I had to make time to learn this and fast, so I looked up sheet music and just started playing. I really got into the A section's chord progression. It's very Hisaishi-coded to me, in context with the melody. Then I came back here, saw the last example in your reply, and had a good laugh. They're the same chords, Cm-Fm-Bb-Eb. I started wondering, is that section of My Castle Town in C minor or Eb major? Is it i-iv-VII-III, or vi-ii-V-I? That pull from V-I feels more compelling to me. I really feel like Eb is the tonic, and honestly I feel that way about This Love and Cruel Angel's Thesis, too. But then again, the key melodies in those sections of MCT and CAT both start on C, which is tricking me into thinking of that as the root of the tonic chord. I'd love to get your take please, but no expectation of a reply for me either!

You know something else, Cm/Eb has been my favorite scale ever since I heard The Girl Who Fell from the Sky from Castle in the Sky. I don't know what it is about those particular notes, but I always love seeing it turn up in other places. Love geeking out on music too, so thanks!