@egonw a few days ago, I bumped the #Bioconda package of r-wikipathways to v1.30 . Thank you for this wonderful package!
Today, after quite some tinkering, I managed to overlay differential expression results. This is not stable code, yet. The enrichment is a bit fiddly and the overlay relies on finding the right offsets in a downloaded path figure. But perhaps, I am naive and there is a better way?