I am recollecting something around this as well, but not sure.
You can use RunJS to set such data so that it does not look this weird.
Or you can create a custom extension which would read the files where you keep this JSON data.
Personally I would not consider that huge in any way. Just a few simple set values.
Big question I guess is how often does the data change?
Personally I like to refresh API actions to ensure the data is up to date.
I have API Acions with dozens of set value steps and they are efficient. Remember set value is a memory based action which executes in milliseconds
For non-confidential data I personally store in public folder and then do an API Action to grab it. Reading from filesystem would be neat but maintaining schema would be tricky in a custom extension