Plasticity is known to require more substeps to converge than models with linear elastic materials.

You have to make a choice on how you want to spend your time. You can either use a small number of substeps, constantly monitoring the N-R plot and making adjustments to minimize the number of iterations, OR you can use a large number of iterations, walk away and do something else then return and be more likely to see the model converge to the end.  If you use a small number of substeps and walk away, you are less likely to return and find the model has converged to the end.

If you are going to run the model many times to get some parametric curve, then it is valuable to tune the number of substeps to minimize the total number of iterations.