Resuggesting! Many thanks to Icycrevasse for the help and Blaze for letting me know of the new sale!

Item 1

https://backpack.tf/item/12966426703

Sale #1

Untraceable-

Seller: https://backpack.tf/profiles/76561199059698603#!/compare/1685491200/1685577600

Buyer: https://backpack.tf/profiles/76561198131839471#!/compare/1504310400/1687910400

Item 2

https://backpack.tf/item/10495705176

Sale #2

Bulk Sale-

Seller: https://backpack.tf/profiles/76561198380713242#!/compare/1685750400/1686096000

Buyer: https://backpack.tf/profiles/76561198079001732#!/compare/1686009600/1686096000

Sale #3

Bulk Sale-

Seller: https://backpack.tf/profiles/76561198079001732#!/compare/1686096000/1686182400

Buyer: https://backpack.tf/profiles/76561199370694017#!/compare/1686182400/1686355200

Sale #4

Bulk Sale-

Seller: https://backpack.tf/profiles/76561199370694017#!/compare/1686355200/1686528000

Buyer: https://backpack.tf/profiles/76561198101261268#!/compare/1686355200/1686441600

Sale #5

Untraceable-

Seller: https://backpack.tf/profiles/76561198101261268#!/compare/1686441600/1686614400

Buyer: https://backpack.tf/profiles/76561199246033009#!/compare/1686528000/1686614400

Sale #6

Untraceable-

Seller: https://backpack.tf/profiles/76561199246033009#!/compare/1686528000/1688428800

Buyer: https://backpack.tf/profiles/76561199446736742#!/compare/1686441600/1686528000

Sale #7

Bulk Sale-

Seller: https://backpack.tf/profiles/76561199446736742#!/compare/1686441600/1686528000

Buyer: https://backpack.tf/profiles/76561198071610485#!/compare/1686441600/1686614400

Marketplace.tf Sales

https://marketplace.tf/items/tf2/31198;5;u186

MP.TF Sale #1

Sold for $31.11 on May 16, 2023

Keys @ $2.02

31.11/2.02 = 15.40ish keys

MP.TF Sale #2

Sold for $34.90 on June 29, 2023

Keys @ $1.97

34.90/1.97 = 17.72ish keys

MP.TF Sale #3

Sold for $25.95 on July 17, 2023

Keys @ $1.97

25.95/1.97 = 13.17ish keys

Sales @ 13, 15, 18

Taking 13-15 here