Uh, dynamic range is a ratio. Loudness is not a ratio. Loudness I.e., level is what the remastering engineer can boost since the peaks of dynamic range will be lower when he compresses it. You wouldn’t want to blow up someone’s precious iPod, would you? You cannot get more dynamic range by turning up the volume however. In that sense they’re not related. They’re not related mathematically. For a given CD the DR is constant. Loudness obviously is not a constant.
Why Does All Music Sound the Same; An Explanation
Since the topic of music production, mastering, and the Loudness Wars comes up frequently on the forum, here's a good tour through the process.
(It's a few years old but still very relevant).
https://medium.com/cuepoint/why-do-all-records-sound-the-same-830ba863203
(It's a few years old but still very relevant).
https://medium.com/cuepoint/why-do-all-records-sound-the-same-830ba863203