Json object - get a property without quotation marks

I have followed instructions in “Ninox HTTP Calls” manual where it says

...JSON objects.

Get a property
The dot notation gives easy access to properties. Examples:

response.result.id
response.result.fields.'First Name'...

But when I tried to get a value containing string value ob.key it returned me string inside quotation marks. To get rid of them I used substr(text(ob.key), 1, length(text(ob.key)) - 2) 

It is a lot of extra functions just to get a value as it had to be, so maybe I am doing something wrong?

P.S. As far as I experimented I can see that there is currently no support for updating values inside arrays or objects after they have been declared. I am right? For example array[0] := value or item(array,0) := value or object[“key”] := value or object.key := value

P.S.S. How do you put " " and ' ' on an iPad? Because those keys that are in its keyboard enter “ “ and ‘ ‘ . And because Ninox doesnt approve that, every time I need to select somewhere, copy and paste it. I have keyboard set to English (UK) in settings.