Thanks for the post.
I have checked the document, and do not find that the u-boot feature is removed from the generated code style with DDR tools.
But since several year ago, the BSP for S32G has moved the DDR code to TFA
Instead of the u-boot, as a result, you may have a try with the DDR tools in S32DS3.4, also I suggest referencing the DDR code structure from BSP31 or a little earlier. In which the DDR code are located under u-boot.
Sorry for your inconvenience.
BR
Chenyin