Hello,
1- Regarding hiding the HTML Block for the Checkout page only, please try using the below Custom CSS code and paste it to Dashboard >> Theme Settings >> Custom CSS >> Global CSS section:
.woocommerce-checkout .elementor.elementor-17182 { display: none !important; }
2- Regarding the Header mini cart element, under the Dashboard > WoodMart > Header Builder > your current Header layout > edit the Cart element > you will find three options there: Hidden Sidebar, Dropdown and Without. You can select that best suits you: https://snipboard.io/TEIK3c.jpg
Further, for the Action after add to cart, under the Theme Settings > Shop > Shopping cart widget > Action after add to cart > there you can select the option of your choice: https://snipboard.io/FzWNbX.jpg
Hope this helps !
Best Regards