While it's not super helpful, generation is the most useful singular spec to tell CPUs apart these days. Even the i3/i5/i7/i9 branding breaks down, since a 12th gen i3 can perform as well as an 11th gen i5.

GHz doesn't really matter anymore, except when comparing CPUs within the same generation.

To get a clear idea of what really differentiates one CPU from another, you pretty much have to look at benchmark scores. There's just too many variables to meaningfully compare on paper.