In retrospect I probably should have donated my G6 GXP, but ahh well, spilled milk and all that. I did get 14 years of fun out of her, so I don't look at losing all the value on the trade-in as a major loss (especially because she was well-loved and looked the part

).
I really think the Stingers can go either way--as in they could become retro popular in a handful of years, or just completely lose value. Everything I have read about the Stingers is that they tend to be pretty tunable, can be made even quicker than they are pretty easily, and while there are reports of stuff going wrong, it seems to me that it tends to be less than some other cars around the class they are. I could see in the future once this supply chain nonsense ends that they go cheap for awhile but someone picks up on them on the social media platform du jure at the time and all of a sudden, people want them again.
However, how far out would that be? (speculation on my part of course). 5 years? 10? By that time it might have flushed out every owner who wants to trade cars in every 3-7 years.
But, on the other hand, they might not ever get a higher priced resale because it seems to me that the great unwashed have been lusting after SUVs for at least the past 2 decades. Why would that change? I see no indication that it would. That might stimulate a market for sedan fans, but maybe not for the general populace enough to bring up KBB values beyond the normal depreciation.
Again, spitballing on my part. Like you I expect to enjoy the hell out of my Stinger for years to come. She's been a dream to drive.