I can run Stardew with no problems, but SMAPI tells me the config file isn't valid: While the game itself runs fine, this means I can't use any graphical replacer mods. https://smapi.io/log/6ecb2ae3386849a8bd820b62914fb820
Did you try re-downloading ContentPatcher and updating it? Completely delete it from your mod folder when you reinstall it, looks like there is an issue in the JSON file from the file you currently have installed.