strong textFor 100k tracks a i7 will be more than sufficient for at least double or triple that.
If you are only running a few zones, less than 6 of concurrent playback, or excessive DSP such as DSD upconversion a NUC10i5 would also be fine.
For ROCK it’s all about the single thread performance.
See this comparison What's coming in Roon OS 2.0 (not Roon 2.0, but Roon OS 2.0)? - #454 by simon_pepper
Also my comments about coming from a NUC5i3 used with ROCK since 2016 to a NUC7i7DNKE (which is a Gen8 NUC with quad core CPU) I have not noticed any usable differences in my setup with a library of circa 100k (8k albums) on a NAS with RAID1 10TB volume (my library is 65% 24-bit HiRes and no lossy formats in the rest).
So for most Roon users a NUC10i7 is totally overkill.