$.PaymentAdvice.PaymentExplanation.Item[*].WithholdingTaxAmount   Isn't all your node inside the "PaymentAdvice.PaymentExplanation",  what is Item[*]? I think the issue is in the schema structuring.

There is no sorting script in the form. I tested with some test data and the issue is not replicated. Can you please check your data if it is coming correctly? There is simple mapping in the form.

Send sample data and schema too.

Have you found any sorting scripts for the mentioned column? Share the form if you can (vkatoch07@gmail.com) will have a look.

Please follow this: https://experienceleague.adobe.com/docs/experience-manager-learn/forms/creating-your-first-adaptive-form/create-adaptive-form-template.html?lang=en 

Have you enabled the template? You need to enable it. Execute the following steps to enable the template:Tap Tools > Templates.Navigate to the  template, select it, and tap Enable.Tab Enable again to confirm.

If subform are placed on different master pages then I don’t think so space can be managed, because they are on separate pages.

For the header you can use a table with a header, table header can span multiple pages if having the header on a dynamic table is needed on each page. Conditional Breaks section is there in the designer but that is for a specific subforms/table if we want to break the subform/table based on some con...

You can have more than one content area inside a master page but when you place a specific page on a master page it will start from a new page. That's the purpose of the master page to have different styles for different pages.

Share your form @ vkatoch07@gmail.com. I'll have a look.