the conqueror was resold for 82 keys and half a key in ref (so ~83)

https://backpack.tf/profiles/76561198339104273#!/compare/1759449600/1759536000

This would make the trade 83-2 = 81 keys.

Other sales here:

https://backpack.tf/profiles/76561198268187402#!/compare/1760832000/1761004800 added a bunch for a bubbling luchadore, could be used there

Looks like it sold for these 3 unusuals + 5 keys

https://backpack.tf/profiles/76561198124356274#!/compare/1761782400/1762214400

https://backpack.tf/item/7622653754

https://backpack.tf/item/13374362129

https://backpack.tf/item/7622653754

Hedge is just outdated at 23, has sellers at 20

Bootlegger just outdated at 28, sellers at 26

https://marketplace.tf/items/tf2/31309;5;u258 kraken has 2 sales at 40$ here, which would be 21 keys at both key conversions (1.89 and 1.88 respectively)

So that will be roughly 72 keys

It might be worth it to verify the values of those hats beyond the sellers, but just to give you an indication.

Those two sales could give this a range.