OP, my threshold for trade with a dealer is KBB Private Party Retail value for my vehicle, and "best going rate" for theirs. For example, if I can find a dealership in California that moves 2000 cars a month, and they will sell the IDENTICAL vehicle to me for a certain price, then that's the price. I will pay doc fees equal to the plane ticket though, as a kick-back to the dealer, usually under the guise of "This dealer has treated me great, and I'd like to keep my dollars local.".
So if you're expecting more than KBB PP retail value (minus any mechanical work needed), from a dealer, than yeah, you're asking too much. If you're not, then keep pushing until you get what you want.
Based on what you posted, I put your car as in "GOOD" condition, and checked very box but NAV (as you don't have a NAV screen I can see). Private Party Retail is $3,726-5,277. However, it is "an SS", so you have a bit of an "intangible" there. If a dealer offered you $5K, I'd take it in a heartbeat!!!! However, I'd post it for $7800 and let someone on Facebook marketplace talk me down to $6K. If that didn't work for a few months, take it t o $6800 and lower expectations to $5K. Also keep in mind...every mile you put on it, is a mile that something expensive could break.
*My numbers are pretty high. You live in Oklahoma. I'd be happy to pull $5K for it from ANY source, were I you. My opinion is that you think too much of your car and need to just keep it, because noone values it as much as you do, based on your postings.
Keep in mind no mainstream dealer will off you more than wholesale auction price, because that's where your car would go. Not even a wax job. Straight to auction block. On MOST non-diesel trick domestics, 100K is a pretty hard cutoff for auction. With Japanese cars, it's more flexible.