Accessing the option to change theme doesn’t seem possible in Safari on iOS as it’s hidden off-screen and won’t allow window to scroll in to view.
Setup information
Ghost Version
5.75
Node.js Version
If self-hosting - share which version of Node.js you’re using.
How did you install Ghost?
Provide some details about your install of Ghost if you are self-hosting.
Provide details of your host & operating system
Include further details about your hosting and OS.
Browser & OS version
Safari, iOS, both iPhone Pro and iPhone 12 Mini
Relevant log / error output
Reported here, but automatically closed: Option to change theme is inaccessible in Safari on iOS · Issue #18627 · TryGhost/Ghost · GitHub