I don't recall anyone else previously reporting holding on to a Platinum card (most people dump it if they can't upgrade it to Signature), and then applying again while still having that Platinum card open.

So I don't know if we had any datapoints on whether applying while having a Platinum card is any different than applying while having a Siganture card. Maybe it is? (But it's hard to be sure from just from your one datapoint.)

Or maybe it's how long you've had the card that makes the difference? Again, most people who try to apply for another card because they another open haven't waited two years. And thus fairly few and rare datapoints on that too.

So I don't think you can extrapolate from a datapoint about Platinum card open two years that you're more likely to get approved for a third card very soon (than people from datapoints in recent months).