Actually to use the word day in the OT does prove the point.
As previously noted day plus the ordinal number is understood to be a 24 hour day as we understand it.
In other places in the Bible the word day is used as a general time such as in the day of the Lord.
So yes, there are instances.
Again, the point here is to let the Bible interpret the Bible.
“let the Bible interpret the Bible”
Of course....
That’s how we ended up with hundreds of Christian denominations.....
So, is it the Bible’s fault, or the Holy Spirit’s?