When does the purchase car make sense?

Good morning, have my Mazda 3 Fb Skyactive-x 2.0 M-Hybrid EZ 02/20 20,000km mileage, I-activesense, BOSE sound system, design package, now since c.a. 70 days on Mobile.de / Classifieds / Cars cout etc but did not have a single interested despite premium ads. The car has a repair accident damage, does it possibly have something to do with it? Reperature costs were around the 3000€ At a Mazda dealer I would get almost 1800€ and at WKDA yesterday I have an offer over 18 500€ received. New price was 26700€ due to cash payment and commercial purchase. Have no experience regarding car sales, therefore I wanted to listen here what you think. Car is registered but I don’t drive with it anymore. How will the value loss be in the next weeks / months? How will the offer of WKDA develop in the next time? Does the waiting generally pay or rather take the WKDA offer with you? What do you think about private for a price? Thank you and greetings, Jonathan