I probably didn’t bring up detailed analysis of this issue, but I posted my experience about a sudden performance enhancement with the release of Build 988. Roon 1.8 (Build 988) - Finally!
Since then, the situation has been up and down with each release. I still have a sneaking suspicion that this is a software (Roon) issue, but perhaps the way Roon manages the searching may differ for different setups.
My hope is that Nucleus+ may solve this issue, not because of its hardware performance, but rather it is supposed to be properly optimized software-wise.