ortho-k might be able to slow down development, but I haven't seen evidence it can reverse it. The NIH in the US claims ortho-k works for slowing down development https://www.nih.gov/news-events/news-releases/multifocal-con...

But on the other hand, the UK NHS guidance https://www.nhs.uk/conditions/short-sightedness/ says that multifocals may help slow the development, while "Some opticians may advise wearing a special lens overnight (orthokeratology). This can help you see better without glasses or contact lenses" (so the UK guidance does not list ortho-k in the list of things that can slow development, only that opticians may advice using it)