After using the Migration Assistant, the 'buy button' is shown in the product listing page even when a product has multiple variants and the main variant has stock>0. Only when the main product stock=0, the 'details' button is shown. In case of variants, the 'details' button should always be shown in listing pages, as without the customer will buy the main product when clicking on the 'buy button'.

Cause: the radio-button 'main product' in the Shopware 6 backend that forces to show the 'detail' button in frontend in case of multiple variants, is not selected after migration. Normally, you have to select 'main product' or 'variant', it's not possible to leave both unselected. See screenshot.

Shopware Support agrees that it doesn't function as could be expected and suggested to correct directly in the database (if you have the knowledge 'how to'). But in fact it can be considered as 'bug' in the Migration Assistant as it doesn't respect essential settings in Shopware 5 properly.