The sale in item 1 is bulk for the Stormy Storm Soldier's Stash (still unusable here so your suggestion is fine :) )

https://backpack.tf/item/15062740452 — Tradeback. Then:

https://backpack.tf/profiles/76561197975508167#!/compare/1755820800/1755907200 — 40 keys + Frankencharged Hellish Overlord

https://backpack.tf/profiles/76561198345091534#!/compare/1755648000/1755907200

https://backpack.tf/suggestion/689eee005d43d3d99c09ebd1 — Open suggestion for Frankencharged Hellish Overlord (170 Keys)

https://imgur.com/J0iolwn — Capped @ buyout of 208 Keys

https://backpack.tf/item/15049612072

https://backpack.tf/profiles/76561198981127656#!/compare/1752192000/1752883200 — Untraceable

https://backpack.tf/profiles/76561199581722058#!/compare/1755129600/1755216000

https://backpack.tf/profiles/76561199581722058#!/compare/1755734400/1755820800 — 147 Keys

https://backpack.tf/profiles/76561198053783254#!/compare/1754524800/1755907200

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147— 208 should work here.