magento2 – Warning: Illegal offset type in isset or empty Magento 2.4

I’m creating basic Module call CustomApplication also I’ve create a table call vendor_application. When I try to submit my form I get this error Warning.

Illegal offset type in isset or empty in
C:xampphtdocsmagento_newvendormagentoframeworkDataObject.php on
line 191

Here’s my codes :

Submit.php

namespace MKFCustomApplicationControllerIndex;

use MagentoFrameworkAppActionContext;
use MagentoFrameworkViewResultPageFactory;
use MKFCustomApplicationModelFormModel;
use MagentoFrameworkControllerResultFactory;
use MagentoFrameworkAppActionAction;

class Submit extends Action
{
    protected $resultPageFactory;
    protected $FormModel;

    public function __construct(
        Context $context,
        PageFactory $resultPageFactory,
        FormModel $FormModel
    )
    {
        $this->resultPageFactory = $resultPageFactory;
        $this->FormModel = $FormModel;
        parent::__construct($context);
    }

    public function execute()
    {

        // print_r($this->getRequest()->getPost());

        // exit();

        try {
            $data = (array)$this->getRequest()->getPost();

            //print_r($data); exit();

            if ($data) {
                $model = $this->_FormModel->create();
                $model->setData($data)->save();
                $this->messageManager->addSuccessMessage(__("Data Saved Successfully."));
            }
        } catch (Exception $e) {
            $this->messageManager->addErrorMessage($e, __("We can't submit your request, Please try again."));
        }
        $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
        $resultRedirect->setUrl($this->_redirect->getRefererUrl());
        return $resultRedirect;

    }
}

FormModel.php

namespace MKFCustomApplicationModel;

use MagentoFrameworkModelAbstractModel;
use MagentoFrameworkModelResourceModelDbAbstractDb;
class FormModel extends AbstractModel
{
    protected function _construct()
    {
        $this->_init('MKFCustomApplicationModelResourceModelVendorApplication');
    }
}

VendorApplication.php

namespace MKFCustomApplicationModelResourceModel;

use MagentoFrameworkModelResourceModelDbAbstractDb;

class VendorApplication extends AbstractDb
{
    protected function _construct()
    {
        $this->_init('vendor_application', 'id');
    }
}

Collection.php

namespace MKFCustomApplicationModelResourceModelVendorApplicationController;

use MagentoFrameworkModelResourceModelDbCollectionAbstractCollection;

class Collection extends AbstractCollection
{
    protected function _construct()
    {
        $this->_init('MKFCustomApplicationModelFormModel', 'MKFCustomApplicationModelResourceModelVendorApplication');
    }
}

Folder Structure

Controller
    |-- Index
    |---|-- Index.php
    |---|-- Submit.php
Model
    |-- ResourceModel
    |---|-- VendorApplicationController
    |-------|-- Collection.php
    |---|-- VendorApplication.php
    |-- FormModel.php

Thanks in advance.