Depending on the kind of configuration, different formats might be helpful.

I made up TER, which supports all ASN.1 types (although in some cases there is not a built-in syntax for them and you must write them in terms of other types; however, extensions can be made for your specific application) and is not limited to Unicode, nor does it limit integers to 64-bits (and you can write integers in any base up to thirty-six). You can convert TER to DER (I wrote a program to do this; it is not really intended for an application to use the full specification of TER itself except for using an external program to convert to DER and then use that instead), and you might also make a subset of TER for specific applications.

But, like any other one, it also has advantages and disadvantages (including some that are mentioned in that article; if they look at TER they would probably have criticisms about that too).

There are two kind of criticisms with JSON, having to do with the data types, and having to do with the syntax, and I had mentioned some of these in the past (some of them are commonly mentioned by others too, but some are less commonly mentioned by others).

Another configuration format is the X resource manager format.