Editing a custom field using the API

Question

I'm attempting to edit a field in Drupal using the restui module. It is a field type "Iframe" out of the iframe module and is saved to the database in the node__field_pocdart_iframe table. I can edit the title of the content node with the "Content: PATCH" resource enabled and the python script below, but when I target the iframe field inside that node, it returns 500 Service unavailable: InvalidArgumentException: Field field_pocdart_iframe is unknown. Is the restui module able to edit custom fields? The "Field" resource is read-only. If not, is there a "safe" method of doing so? I'm hoping for a solution that doesn't require editing the database table directly.

Drupal Version: 10.4.0 REST UI Version: 8.x-1.22

import requests
import base64
import json

class DrupalRequests:
    def __init__(self):
        """Init for class ZoomRequest
    
        Initializes ZoomRequest class with a number of environmental variables
    
        """
    
        # request an OAuth access token from Zoom
        clientId = "generic_user"
        clientSecret = "<redacted>"
        authString = clientId + ':' + clientSecret
        self.auth_encoded = base64.b64encode(authString.encode("utf-8")).decode("utf-8")
        # OAuth request headers
        self.headers = {
            'Authorization': 'Basic ' + self.auth_encoded,
            'Accept': 'application/vnd.api+json'
        }
        self.base_url = 'http://<my_ip>/'

    def patch_node(self, path, key, value): 
        headers = {
            'Authorization': 'Basic ' + self.auth_encoded,
            'Content-type': 'application/json'
        }
        
        endpoint = self.base_url + path + '?_format=json'

        data = {
            "title": [
                {
                    "value": "Example node title UPDATED!"
                }
            ],
            "type": [{"target_id":"article"}]
        }

        data_json = json.dumps(data)

        response = requests.patch(
            endpoint,
            headers = headers,
            data = data_json)
        return response


rest = DrupalRequests()
response = rest.patch_node('dashboard/testSchedule', 1, 2)
print(response.content)
print(response.reason)

Adjusted json with the target field:

data = {
            "field_pocdart_iframe": [
                {
                    "url":"UPDATED"

                }
            ],
            "type": [{"target_id":"article"}]
        }

Full error:

b'The website encountered an unexpected error. Try again later. InvalidArgumentException : Field field_pocdart_iframe is unknown. in Drupal\\Core\\Entity\\ContentEntityBase->getTranslatedField() (line 616 of core/lib/Drupal/Core/Entity/ContentEntityBase.php ). 
Drupal\\Core\\Entity\\ContentEntityBase->get() (Line: 140)
Drupal\\serialization\\Normalizer\\EntityNormalizer->denormalizeFieldData() (Line: 59)
Drupal\\serialization\\Normalizer\\EntityNormalizer->denormalize() (Line: 247)
Symfony\\Component\\Serializer\\Serializer->denormalize() (Line: 179)
Drupal\\rest\\RequestHandler->deserialize() (Line: 67)
Drupal\\rest\\RequestHandler->handle()
call_user_func_array() (Line: 123)
Drupal\\Core\\EventSubscriber\\EarlyRenderingControllerWrapperSubscriber->Drupal\\Core\\EventSubscriber\\{closure}() (Line: 638)
Drupal\\Core\\Render\\Renderer->executeInRenderContext() (Line: 124)
Drupal\\Core\\EventSubscriber\\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\\Core\\EventSubscriber\\EarlyRenderingControllerWrapperSubscriber->Drupal\\Core\\EventSubscriber\\{closure}() (Line: 181)
Symfony\\Component\\HttpKernel\\HttpKernel->handleRaw() (Line: 76)
Symfony\\Component\\HttpKernel\\HttpKernel->handle() (Line: 53)
Drupal\\Core\\StackMiddleware\\Session->handle() (Line: 48)
Drupal\\Core\\StackMiddleware\\KernelPreHandle->handle() (Line: 28)
Drupal\\Core\\StackMiddleware\\ContentLength->handle() (Line: 116)
Drupal\\page_cache\\StackMiddleware\\PageCache->pass() (Line: 90)
Drupal\\page_cache\\StackMiddleware\\PageCache->handle() (Line: 48)
Drupal\\Core\\StackMiddleware\\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\\Core\\StackMiddleware\\NegotiationMiddleware->handle() (Line: 36)
Drupal\\Core\\StackMiddleware\\AjaxPageState->handle() (Line: 51)
Drupal\\Core\\StackMiddleware\\StackedHttpKernel->handle() (Line: 741)
Drupal\\Core\\DrupalKernel->handle() (Line: 19)'

500 Service unavailable (with message)