Hi Georgia Hilton,
The subdivision displacement that you get from the Material can’t be converted, to my knowledge, with native tools. (Perhaps there is a python script somewhere that I’m not aware of.)
There are two ways that I would suggest, both use the Displacer Deformer. The first one uses the Object Manager>Object> Current State To Object, and the second one the Correction Deformer.
I have created two clips to show case this: You can download them, for a better viewing experience.
https://www.amazon.com/clouddrive/share/U4qXhpnoLed3NZr8c0T4UT7eBjLsqXRBRg1QIZVhMYQ
Note that when I place a letter into the Material selection, that I use a selection name that doesn’t exist, so the material is off. I do this to showcase the effect, no other reason.
The Correction deformer takes the data and goes from there. If you change your mind with the displacement setting, it creates a mixture of what has happen and what will be the effect of the new changes, and it can go ugly. So, once the Displacer is set up and the Correction Deformer is active, I would not change the Displacer setting.
The first method works on a polygon copy the second one on a memory based copy, each has its pro and con.
All the best