AddCustomInventoryAttributeProgrammatically

db_schema.xml

<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table name="cataloginventory_stock_item" resource="default" comment="Cataloginventory Stock Item">
        <column xsi:type="smallint" name="coming_soon" padding="5" unsigned="true" nullable="false"
                identity="false" default="0" comment="Coming Soon"/>
    </table>
</schema>

product_form.xml

<form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
    <modal name="advanced_inventory_modal" provider="product_form.product_form_data_source">
        <fieldset name="stock_data">
            <container name="magevision_container_manage_stock" component="Magento_Ui/js/form/components/group" sortOrder="2000">
                <argument name="data" xsi:type="array">
                    <item name="config" xsi:type="array">
                        <item name="formElement" xsi:type="string">container</item>
                        <item name="dataScope" xsi:type="string">stock_data</item>
                    </item>
                </argument>
                <field name="coming_soon" sortOrder="10" formElement="select">
                    <argument name="data" xsi:type="array">
                        <item name="config" xsi:type="array">
                            <item name="rawOptions" xsi:type="boolean">true</item>
                            <item name="value" xsi:type="number">0</item>
                        </item>
                    </argument>
                    <settings>
                        <scopeLabel>[GLOBAL]</scopeLabel>
                        <label translate="true">Coming Soon</label>
                        <dataScope>coming_soon</dataScope>
                    </settings>
                    <formElements>
                        <select>
                            <settings>
                                <options class="Magento\Config\Model\Config\Source\Yesno"/>
                            </settings>
                        </select>
                    </formElements>
                </field>
            </container>
        </fieldset>
    </modal>
</form>

StockManagement.php

<?php

namespace MageVision\Blog86\Model;

use Magento\CatalogInventory\Api\StockRegistryInterface;
use Magento\Framework\Exception\NoSuchEntityException;

class StockManagement
{
    private StockRegistryInterface $stockRegistry;

    /**
     * @param StockRegistryInterface $stockRegistry
     */
    public function __construct(
        StockRegistryInterface $stockRegistry
    ) {
        $this->stockRegistry = $stockRegistry;
    }

    /**
     * @param string $sku
     * @param bool $comingSoon
     * @return void
     * @throws NoSuchEntityException
     */
    public function update(string $sku, bool $comingSoon): void
    {
        $stockItem = $this->stockRegistry->getStockItemBySku($sku);
        $stockItem->setData('coming_soon', $comingSoon);
        $this->stockRegistry->updateStockItemBySku($sku, $stockItem);
    }
}