Trying to solve the same problem, and found the solution: (today()-file.mtime).days.round(). Gives the total number of days difference.
I actually use (today()-file.ctime).days.round() + " days (" + file.ctime.relative() +")" for the best of both worlds (note this is created time, not modified)
I came up with something for now that works like this:
Display
“Months Weeks Days” (0 Months, Weeks, Days will be removed)
Today, future and past Differentiation
So Like:
→ 2 Months 2 Days
← 3 Weeks 1 Days
etc.
Havent implemented Years yet.
Its close enough taking into account an average of days in month considering leap years etc.
Here’s the formula. Just replace PLACEHOLDER with your date property.