Removing a tag after a file has been opened

Hey all,
I've been running into this problem recently. I have a rule setup for my downloads folder that any files downloaded from my university's course websites automatically get sorted into the appropriate folder for that course and marked with the tag "Unread." This is so I can collect all the materials I have not yet reviewed. However, I'm having trouble creating a rule that would remove that tag after I've reviewed the material based on the "date last opened" criteria.
My original idea was if date last opened is more recent than date created, remove tag. But since date last opened is already later than date created by seconds/milliseconds I cannot use that criteria. I've thought about trying to use "if opened in the last 5 minutes" but it wouldn't really work for files I open immediately and would instantly remove the "unread" tag for any files that get added immediately from the downloads folder (since date last opened is milliseconds after date created for brand new files).
Anyone have some creative ways to go about removing the "unread" tag once I've opened/viewed a file? Sincere thanks in advance.
I've been running into this problem recently. I have a rule setup for my downloads folder that any files downloaded from my university's course websites automatically get sorted into the appropriate folder for that course and marked with the tag "Unread." This is so I can collect all the materials I have not yet reviewed. However, I'm having trouble creating a rule that would remove that tag after I've reviewed the material based on the "date last opened" criteria.
My original idea was if date last opened is more recent than date created, remove tag. But since date last opened is already later than date created by seconds/milliseconds I cannot use that criteria. I've thought about trying to use "if opened in the last 5 minutes" but it wouldn't really work for files I open immediately and would instantly remove the "unread" tag for any files that get added immediately from the downloads folder (since date last opened is milliseconds after date created for brand new files).
Anyone have some creative ways to go about removing the "unread" tag once I've opened/viewed a file? Sincere thanks in advance.