How it is done
so you can do it yourself
1. Download and install SOMU 1.5
2. Extract Lichess downloads in the PGN folder.
3. Doubleclick SOMU.EXE and press [F8]
4. Select the PGN from the folder.
5. And make the selections of your choice.
6. The result is stored in OUTPUT.PGN
Once you have the human database of 3.784.887 games installed you can extract from that database higher elo rated database such as 2300, 2400, 2500 etc. with SOMU 1.5 [F8].