>>5972999sure friend.
There is very little information on this for some reason. So while I don't really have a particular tutorial I can tell you that you can use surface blur or cutout which is available on photoshop onto an image. From there, you use gradient maps to remap the colors from the photo to match what you like. Usually this means that you're shifting the really dark blacks to a cool desat blue or desat red if everything in your image is already cool. You can add up layers of soft light to build up saturation and color unity between what you are drawing and the picture. You can also use posterization filter on the image on multiply, add a colorburn layer with outer edges and smooth it for a more illustration look to the image. I think there is an autoaction from csp that does this on the asset store. Then, while you are drawing your characters or non-photobashed elements, make sure to keep that kind of posterized look (very distinct light shapes made with 2 values) so that it blends in without looking weird.
Nobody wants to show their process of photobashing probably because they don't want to show shortcuts that normies would look down upon. I really wish this information was more widely available but it seems like a lot of it you have to figure out for yourself. I hope this clarifies some things for you. I think this process is called matte painting for concept art but for anime art I haven't been able to see any real tutorials. Some people use 3D renders and paint on top with some of the techniques I mentioned, but I'm still very naiive to 3D so I am unable to elaborate on that aspect.
