The goal in attempting to reduce the % difference has always been an attempt to cast doubt on common ancestry.
What I have noticed with YEC and anti-common descent ID is that there is seldom (if ever?) an attempt to make sense of the entire sweep of the data supporting common ancestry. We see attempts to diminish the % identity. We see attempts to show that a few rare pseudogenes have been exapted and now have a new function. We see aspersions cast on incomplete lineage sorting, and so on - but we don’t see a coherent case that explains the data better from an antievolutionary perspective. We don’t even see articles that tackle these diverse lines of evidence in the same article, lest the readership notice the problems, I guess.
The one counterexample I know is Todd Wood’s 2006 article, and he concludes that YECs don’t have a good explanation. That’s it.