problem with putting apps into desktop and with allowing photo access

So, I have tiktok, for some reason it disabled photo access, which it had before, and it doesnt ask to turn it on, as a request, but instead says "turn on photo access" and the button takes me to tiktok settings in the settings app, which doesnt have an option to turn on photo access. Also, I tried to delete it from desktop and see if that would work, but it didnt, how do I return the app to desktop without reinstalling it? (because I have a lot of data in it) and is there a way to make an app ask for photo permission without the settings that dont have that option to allow it?