Using as a mini. Please make corrections if necessary before I posted the main suggestion. Credits to Scourge for help.

Sale #1

https://backpack.tf/profiles/76561198334946156#!/compare/1583712000/1583798400 48 keys

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Sale #2

https://backpack.tf/profiles/76561198334946156#!/compare/1583884800/1583971200 Starstorm Slumber Toadstool Topper (46.5) + 12 keys = 59

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Sale #3

https://backpack.tf/profiles/76561198097271466#!/compare/1583971200/1584057600 51 keys

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Sale #4

https://backpack.tf/profiles/76561198097271466#!/compare/1585785600/1585872000 53 keys

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Sale #5

https://backpack.tf/profiles/76561198057583306#!/compare/1588204800/1588377600

https://backpack.tf/profiles/76561198120672630#!/compare/1588204800/1588377600

Sold with Blizzardy Storm Gentleman's Ushanka + 1 key for a Frostbite Powdered Practitioner

https://bot.tf/stats/listings/Y5Z0QV19 b/o 65 keys

Ushanka (credit to Offline): https://backpack.tf/suggestion/5ec3173c6b8a6f1f5a22f1b1

x + 27.5 + 1 = 83.5

x = 55

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https://marketplace.tf/items/tf2/388;5;u13;strange + https://backpack.tf/item/337414254 $130.99 / $1.79 = 73.18

https://bot.tf/stats/listings/MLVLPJLJ b/o 55 keys

55

Classifieds have buyers at 53

GOING WITH 53-59