I believe the Cars and Bids site may be a better place to sell a 4c here in the US than Bring a Trailer these days.
Interesting assertion, but at the face, the data doesn't show that...
Even when the 4C market was robust on Bring-a-Trailer at the peak (late 21/early 22), 4C's on Cars & Bids were fetching in the low/mid 40s. The 33 Stradale Tributo is an outlier as it's extremely rare version of a rare car -- 33 total made it stateside and I recall that at least one of them was totaled already.
During that peak period, BaT 4Cs did quite a bit better.
Lately, it seems like 4C values have retreated to their pre-pandemic numbers. It doesn't help that there's also a lot of them for sale -- many from folks that bought them during the pandemic peak. Cargurus is showing a total of 38 4C's for sale nationwide. During the pandemic, there were typically less than a half-dozen. For anyone looking for a 4C, there are a lot of options right now.