Does A DSLR APS-C Camera Produce Creamier Bokeh Than A Mirrorless APS-C Camera?

you can put any lens that an APS-C DSLR uses on a mirrorless APS-C body, thus the bokeh each can produce is the same.

if you want the most OOF images, your best bet is using a full-frame sensor with a fast telephoto lens.  a cheap route is to get a used Canon 5D body for $700, and put a $250 85mm F1.4 Samyang on it (manual focus, but it's a pretty decent lens otherwise).  for under $1000, you'll have a setup that can produce huge bokeh than pretty much anything if that's the only thing you are after.

I have a 50mm F0.95 Canon rangefinder lens I modified to fit on my E-M5.  it produces relatively nice bokeh on my E-M5.  ditto if I put my four-thirds 150mm F2.0 Zuiko lens on it.  pick the right combination and even with a smaller sensor you can get good bokeh.  downside is lenses like these are quite costly, whereas it is fairly cheap to get a lens that can produce similar images with a larger sensor.