Incorrect(?) Ghost errors when uploading theme zip file

Ran into issues tonight figuring out how to run Gulp on my local install to create a theme zip file I could upload to my live server. Changing the node version to 14 seemed to fix it. Not sure if that has anything to do with:

When I upload the zip file, I get an error message indicating that something is wrong with the package.json file that is “Highly recommended to fix, functionality could be restricted.” What was wrong with package.json? Ghost said that the “” property was missing. Well, in fact the package.json file did contain the email property, properly formatted. Frustrating and confusing.

In trying to untangle this, I learned that the theme developer had released a new version. So I downloaded the new theme and started over. Now, when I upload the zip file of the theme, it gives me a similar error message. The part is fine now apparently (despite being unchanged) but now Ghost is claiming that a custom setting in package.json “hasn’t been used in any theme file” – and yet, the custom setting in question (@custom.show_dark_mode_switch) is in fact used (twice!) in navigation.hbs.

I guess I could carry on and just not worry about this – the theme seems to work fine otherwise – but it’s bugging me, and I don’t like the annoying big red error message in my Ghost admin. Any ideas? Thank you!