I tried Movavi a couple of weeks ago, hoping to lessen my initial despair at the loss of the retouch brush. It didn't work for me at all and, as I couldn't figure out why, I just decided not to bother with it. Next I tried PicMonkey. The retouch brush seemed similar to that of Apple but, again, when I tried it, nothing happened, (i.e.., centered the circle over a speck of dust on my photo, clicked, and... nothing happened.) So I emailed a request for help. Two days later I received a reply which was not helpful. A conversation began with them. A day later, a different person responded basically repeating the same info that hadn't worked the first time. And a day after that, a third person contacted me asking if I had "separated my layers". Huh? Okay, but I made it clear that I'm strictly a black and white photographer. Nobody listened. So that's another option down.
I don't have faith that Apple will replace the retouch brush any time soon. I will clean certain of my negs and rescan, hopeful to rid them of dust.