You've not included the marketplace.tf link for these sales. Or the histories/buyouts for them

Here's the histories for this hat:

https://backpack.tf/item/9248534320 - likely a Marketplace.tf sale, worth checking for a buyout

https://backpack.tf/item/9188943653 - looks like a lot of non-marketplace.tf sales

https://backpack.tf/item/8710200879 - likely one of the marketplace.tf sales

https://backpack.tf/item/6969410296 - sales to and from r+ubi should be included here too

Have you fully read the Unusual Suggestions guide on the forums? - https://forums.backpack.tf/topic/6033-rules-for-unusual-price-suggestions/