Can't update OSMC or change kodi settings

Yes, sounds like a valid action plan.

Perhaps you want to try to save the current SD image and reburn it to a new SD card using

h2testw is a nice and easy tool running on Windows to test such SD card, it also has an English language setting, H2testw | heise Download

Before running h2testw you have to reformat your SD card, SD-formatter is an excellent tool for this SD Memory Card Formatter for Windows Download | SD Association