How to output an array of strings in modx?

Question

MODX

There is a json type resource that generates a set of parameters for the website calculator.
For example, there is a text field, it is written in the format "brand1", "brand2", "brand3"
I want to write on each line
brand1
Brand2
Brand3
To format it into an array above (in quotes, separated by commas). Last element without comma
PS Brand for example - I have each array contains more than 100 elements. Accordingly, migx is not an option.
View of the final file mango-digital.ru/insurance.json (prices, countries are displayed there) And all this disgrace is stored in this form in the admin panel. There is a very big chance that managers will break everything