Ripoff of "Seconds" (1966)?

Then I can't confirm or deny if it is a homage or ripoff. Sorry

You're probably right. To be fair, it probably lifts more from Oscar Wilde's 'Picture of Dorian Gray' (there's even a literal huge portrait of herself that she stashes away, as well as her other self....).

I mean, all the stories have already been told, it's more the way they're being told. Which is why, personnaly, I never minded remakes and, as long as we're talking cinema, I'm less bothered by intentional or "accidental" similarities between pure plot elements than by a director copying the frame composition/edition/lighting, etc. (mise-en-scene: the purely cinematic elements of a film, so to speak...) of another. 'The Substance', if it wasn't a film, would be the Frankenstein monster (perhaps even so by design, one theme of the film being monstrousness...) because it's composed of bits and pieces of shots from other films that cinephiles over 40 will instantly recognise.

As for so called 'homages', I feel like if you're not already at least a little bit established as a remarkable director or have a at least one remarkable film under your belt and have demonstrated that you've brought your own style to the table, then basically who the fuck are you that we should be interested in what your cinematic references are or where you come from? It's like writing a memoir as your first book. So to me it's merely lazyness and piggy-backing on greater artists.