I assume the archive type used is .zip ? you did not mention.
I've managed to carve through the content, and i've not found anything related to bitcoin, yet.
From testing zip and rar files with both normal archives and encrypted with password, some of the content should still be possible to read in hex, at least that was possible for me when i tested with just a .txt document inside a test zip and rar archive.
I've had no luck finding any password protected files (the 2 types possible to create in modern day zip)
Is the file you're looking for named: recovery.txt ? i've found information about a file named that, that file was created in july 2017
was only two write sessions first in 2010, second two years later, wish I printed private address part on paper medium
it was exactly 10 BTC, possible scan explorer for that period and find BTC address that received exact amount and staying dormant