I don't think most dealer trade-in offers are genuinely ever "fair". But what they are is no-hassle money if that is what you want. In this market though I think the minimal price tag should be what you originally paid. It shouldn't be hard for you to find a local that would jump at paying original price for a Maverick in this condition. You know the dealer won't sell it that low so you know they wouldn't be squeezed by paying original prices. There are STILL dealers today that will pay MSRP to get a hold of a 5 year old Silverado/F-150. Mavericks have the same demand and rarity so I would expect the dealer to be able to do more.
Sounds about right in a normal market which this aint. Id try all the online buyers like vroom/carvana and see what happens. You dont have to guess or wonder if the dealers are lowballing anymore, you can just sit on your rump and type in a few pieces of info and find out.