Is there a way to change time when posted and change to the full time and date?

There is the Relative date duration site setting, which allows you to configure the number of days after posting in which the date will be shown as a relative instead of an absolute date.
So instead of:
You get
But I think this doesn’t help for the first 24 hours. By default, it also doesn’t show the time. You could add that by customizing the site text for dates.tiny.date_month to llll
But while that looks okay on posts
It needs a lot of space in the topic list (and probably also in other places)
What is your use case for showing absolute dates? You can currently see them on hover, and when you click the time, so there is even a solution for touch devices.