9890 Clogged black

Hello. I have a clogged black head and have tried about everything. Replaced scrapper, swapped blacks, 2 days with Piezo fluid on paper towel left overnight, then during the day changed and “shoe shinned” over head every two hours. In that I have managed to unclog a few(maybe 5-10% of nozzles) but that’s it. This is where I am(see below)

Has the internal Piezo flush had a high success rate? I can get a new Epson once they start shipping again after the first of the year but would love to fix this one until then. If I know it has a high chance of working great but don’t want to drop another $500 in this printer if it won’t.Thoughts? Thanks