^^^ A walkway smaller than 15 inches??

Just sayin' Mulch on the edges. Not arguing.

Electric - 2000 or 2500 I think :confused:

You're talking about outside?

Well stop pressure washing for one thing. It's driving all of the stain further into the concrete.

Just leave it alone, and the sun's UV rays will make it fade out.

Park your air cooled Porsche over it. After a couple months you won't see the coffee stain under the oil drops.

If no air cooled Porsche, muriatic acid. Bleach first, then wash down. Add muriatic acid and it should destroy the dna.

That should be enough pressure if a pressure washer would make it go away.

I usually find they fade a stain.

Don't know your location but a TSP slurry allowed to sit on the stain may help.

https://www.homedepot.com/p/SAVOGRAN-1-lb-Box-TSP-Heavy-Duty-Cleaner-10621/202935861