Opened the application on Windows and it was completely back to default. Everything was still ‘there’, so to speak, just turned off and reset. Plugins and themes were downloaded but not enabled, and all application settings were reset to default. Note though that I sync my vault between devices with iCloud, and my phones vault is still the way it should be!
Rebooting the application and opening it on another device (iPhone) to try and force an iCloud .obsidian file refresh