My own experience has been very good with Samsung / MTR
Whilst you say no damage to the screen, you are only looking at the front facing element.
Samsung / MTR have access to very clever software on your device and tech that can see under the screen and inside devices to check for damage.
They found some. Hence the change in trade in value.
I am not employed by Samsung nor do I receive any remuneration as a Samsung Members Star.
My device is an S25 Ultra.