@bit That may be more difficult than it seems, as Bitwarden also considers – in a more broad sense – using the copy buttons (copy & paste) and using drag & drop as “autofill options”. So, should using those autofill methods count as “last filled” or not?
I think you might profit from this other feature request here as well (i.e. using expiration reminders probably would solve your issue as well – essentially for that feature it wouldn’t matter if the password or the account expires…):
PS: And I think, without a sorting option for “last filled”, it would become tedious to search hundreds of vault items for “last filled”…: