Resuggestion, thanks to Mindacos for the info!

Sale 1:

https://backpack.tf/profiles/76561198083224675#!/compare/1569628800/1569715200

https://backpack.tf/profiles/76561198155512809#!/compare/1569974400/1570060800

Untrace

Sale 2:

https://backpack.tf/profiles/76561198236284774#!/compare/1565913600/1568505600

https://backpack.tf/profiles/76561198151652607#!/compare/1559952000/1568419200

SCM

Sale 3:

https://backpack.tf/profiles/76561198354692517#!/compare/1565913600/1566432000

https://backpack.tf/profiles/76561198289369937#!/compare/1566345600/1566432000

Sold for 10 keys

Sale 4:

https://backpack.tf/profiles/76561198289369937#!/compare/1566691200/1567036800

https://backpack.tf/profiles/76561198815908394#!/compare/1566345600/1566777600

Sold for 10 keys

Sale 5:

https://backpack.tf/profiles/76561198815908394#!/compare/1567382400/1567468800

https://backpack.tf/profiles/76561198068732040#!/compare/1567382400/1567468800

Sold for Steaming Cowl

use there

https://bot.tf/stats/listings/Y8E16V7W

B/O of 11 keys

Sale 6:

https://backpack.tf/profiles/76561198796481113#!/compare/1566172800/1566345600

https://backpack.tf/profiles/76561198211276789#!/compare/1566259200/1566345600

Sold for 5 keys(?)

Sale 7:

https://backpack.tf/profiles/76561198211276789#!/compare/1566345600/1566604800

https://backpack.tf/profiles/76561198110534225#!/compare/1566518400/1566604800

Sold for Clair Tank + negligible sweets

Tank Mini:

https://backpack.tf/suggestion/5d9f9a55d38172593666ad63

Suggestion for 9.5 keys

Total is ~10 keys (sweets round up to 10)

https://bot.tf/stats/listings/Y35G9D9R

B/O of 16 keys

Sale 8:

https://backpack.tf/profiles/76561198239327232#!/compare/1568419200/1568505600

https://backpack.tf/profiles/76561198102241733#!/compare/1564963200/1568505600

Can trace a key

Sale 9:

https://marketplace.tf/items/tf2/219;5;u60

$18.6 / $1.80 = 10.33 keys

total sales @:

10, 10, 10, 10.33 keys

Mindacos' Part:

New sale:

Quicksold for 7 Keys

https://backpack.tf/profiles/76561198155512809#!/compare/1573430400/1573516800

https://imgur.com/a/MZl7950

https://backpack.tf/item/7956008586

Unsold for 1+ month at ~9.4 Keys, relisted at 9.2 Keys.(creds k1ng)

Not sure if I missed any other new sales, but you'll probably need to include this seller in the range at least.

Taking 9 - 10 keys