Hi @NavNig-9720, welcome to Microsoft Q&A forum and sorry for the trouble you have been facing.
JSON functions are supported in Azure Database for PostgreSQL. I followed up the below article and tried multiple JSON functions and was able to run them properly in the database.
Below is the list of functions I tried:
json_each()
json_object_keys()
json_typeof()
I created the Azure PostgreSQL with version 11.
Is it possible for you to share few functions that did not work for you, so that we can verify them by running at our end. Also which version of Azure PostgreSQL are using?