Here’s how to create a custom thank you page:
1. Go to WordPress Dashboard.

2. Select ProductX, then Go to WooCommerce Builder.

3. Select Add thank you. Select Start from scratch (if you want to make it from scratch) or Import a template (if you want a premade template).

4. Name your Template, click the icon (toggle block inserter), and then add the desired Blocks to complete your thank you page. Now hit Publish.

And you have successfully created your custom thank you page.