The preferred solution for this issue would be to have specific tuff versions of ores.
When replacing tuff, ores generate with a stone background instead of the characteristic deepslate that is intended of this y region. This is due to tuff being in the wrong block tag. Tuff appears to sometimes be replaced with proper deepslate ores, but this is rare (one example attached) and is probably caused by actual deepslate coincidentally being in that position..
This could be cheaply fixed by simply making that which replaces tuff be deepslate instead, but a preferable, much more elegant solution would instead be to add tuff versions of ores.