>>Is there a method for that json file to be directly ingested in to site 24x7?
Yes, its possible using Site24x7's Custom Plugins.
You can write your own plugin and place it in Site24x7WindowsAgent Plugin's folder
Eg: "C:\Program Files (x86)\Site24x7\WinAgent\monitoring\Plugins".
The plugin will then be automatically detected by the Site24x7WindowsAgent and be executed at every 5 mins interval.
As per your requirement, you can write a PowerShell plugin, that performs the SQL agent jobs to run series of queries and provide that script output in JSON format.
But, make sure the plugin's JSON output has certain Mandatory Parameters. Find our help documentation below that will guide you through writing a plugin along with a sample plugin file for your reference.
Hope this fulfills your requirement. Please let us know for further specifications or queries, if any.