I have exactly the same issue. Running Mathematica on Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz this is my result
- 12.1: "BenchmarkResult" -> 2.951, "TotalTime" -> 4.69
- 12.2: "BenchmarkResult" -> 2.643, "TotalTime" -> 5.23
I've found, in general, Mathematica 12.2 to be much slower than 12.1, so that I've decided to work on 12.1 version.
Does anyone know how to fix this "bug"?