A second Kampbelmann Hard is tough on paper, but gives way routinely to a systematic bypass.
Here is the grid well into the bypass, with a large number of cells held in reserve by box filling naked pairs.
In the trace, we’re at value 9, just before r5[258] is resolved.
The rest is routine follow up.
Next week, the third and last Kampbelmann, Hard 143, is harder, carrying into line marking, after giving an opportunity to show a box 3-fill (West) in the trace.
Systematic Sudoku 