I have used 0-9(including the professional system). I like it. I don't have chemically altered hair (color, processes, relaxer, etc) and I do not Olaplex products back-to-back or in a daily regimen, but when I sprinkle it into my regimen, I enjoy it. You should be leery to use it. This line has lawsuits and complaints against it that should give pause, at minimum. However, that is going to be an issue for any line that is marketed towards people with compromised hair and who use chemical services. It is pretty hard to tell if Olaplex damaged their hair, if Olaplex exacerbated existing hair issues, or if the normal risks of chemical services ran their course...despite Olaplex use. I began using Olaplex a bit more frequently than I currently use it after my setback at the end of 2021 and consider it beneficial to my regimen. It didn't repair the damage but he helped me stretch gradually cutting my damage off. I intentionally avoid using it when I am cutting my hair because I want to see what needs to be cut not mask it.
