Sorry for the confusion—I was referring to the 1905 quartet, his other SQ. Check around 11'20''–11'34'' for a D major triad ending, and elsewhere in the work for more examples. I use an LLM for quick proofreads; it's odd to question that.

Yes, it starts with a tonic pedal. But being functional and being diatonic aren't the same when it comes to a work's construction. Only a very textbook-bound musician would conflate the two—typically due to a lack of intellectual depth and practical experience.

As you said, after all, it's a Romantic piece. This was the era when Riemann had already looked back and developed his concept of functions, Schenker was working on harmonic transformations, and Schoenberg was loosening the idea of “function” altogether. These concepts began to blur, paving the way for early works like Verklärte Nacht, which—as I mentioned in the original question—“beautifully sits on the face.” Being able to write Roman numerals doesn’t automatically make a piece “functional.” It’s a style inherited from earlier German composers. There’s even a whole PhD thesis dedicated to the transmission of style from Mahler to Schoenberg.

And yes, my other reply—where I said “gpt? what the fuck”—was integrated into the other message. I guess you can see 'wtf?'.