I have two DMT diamond stones in coarse and fine. They both do the trick and can be run wet or dry. I also have a set of cheap Chinese “whetstones” from Amazon. Gotta say that both sets are able to sharpen my knives. The diamond stones I find way easier to use and a lot cleaner.
Cleaner in the sense you don’t have the whetstones forming a slurry on top while sharpening as cheap stones tend to do. A slightly damp paper towel will clean off any metal shavings if the diamond stone is used dry. I don’t think this is a problem with high quality whetstones.