jsonb_set not working as expected with nested collections, resulting in null value returned - sql

Question

I am trying to update a nested collection in my Postgres table using json_set, however, my approach is resulting in a collection of null values.
id
payload
row_version
fbfd3b9d-bb20-4c1b-985f-0979890472ec
{ "slots": [ { "bannerXCreatorSettings": { "additionalFields": [ { "label": "test-label", "enabled": true, "mandatory": false, "additionalFieldId": "label", "maxCharacterLimit": 22, "additionalFieldType": "TEXT", "colorHexOptionsList": [] }, { "label": "test-label-2", "enabled": true, "mandatory": false, "additionalFieldId": "label2", "maxCharacterLimit": 55, "additionalFieldType": "TEXT", "colorHexOptionsList": [] } ] } } ]}
1
I have the following json payload stored in my table:
{
"slots": [
{
"bannerXCreatorSettings": {
"additionalFields": [
{
"label": "test-label",
"enabled": true,
"mandatory": false,
"additionalFieldId": "label",
"maxCharacterLimit": 22,
"additionalFieldType": "TEXT",
"colorHexOptionsList": []
},
{
"label": "test-label-2",
"enabled": true,
"mandatory": false,
"additionalFieldId": "label2",
"maxCharacterLimit": 55,
"additionalFieldType": "TEXT",
"colorHexOptionsList": []
}
]
}
}
]
}
Within the additionalFields collections, I want to add selectOptions. Like this:
{
"slots": [
{
"bannerXCreatorSettings": {
"additionalFields": [
{
"label": "test-label",
"enabled": true,
"mandatory": false,
"additionalFieldId": "label",
"maxCharacterLimit": 22,
"additionalFieldType": "TEXT",
"colorHexOptionsList": [],
"selectOptions": [] <-- new field
},
{
"label": "test-label-2",
"enabled": true,
"mandatory": false,
"additionalFieldId": "label2",
"maxCharacterLimit": 55,
"additionalFieldType": "TEXT",
"colorHexOptionsList": [],
"selectOptions": [] <-- new field
}
]
}
}
]
}
I have written the following SQL to try update the JSON payload within my table:
select
id,
payload,
row_version,
jsonb_set(
payload,
'{slots}',
(select
jsonb_agg(
jsonb_set(
slot_elem,
'{bannerXCreatorSettings}',
jsonb_set(
slot_elem -> 'bannerXCreatorSettings',
'{additionalFields}',
(
select
jsonb_agg(
jsonb_set(
field_element,
'{selectOptions}',
jsonb_build_array()))
from jsonb_array_elements(
slot_elem -> '{bannerXCreatorSettings}' #>'{additionalFields}') WITH ORDINALITY a_t(field_element, idx_1))
)
)
)
FROM
jsonb_array_elements(
payload #> '{slots}') WITH ORDINALITY t(slot_elem, idx))) as payload_update
My understanding of SQL is limited, however, I feel as though this should work. Unfortunally the above query results in the following:
{
"slots": [
null,
null
]
}