If any Magento 2 extensions are not compatible with the Hyva theme, then they will also not be compatible with the pre-built InstaBuild—Hyvä Theme Accelerator. In such cases, you can:

• Look for alternative extensions: Explore other extensions that offer similar functionality and are compatible with the Hyva theme.
• Consider custom development: If a crucial extension is unavailable or incompatible, custom development might be necessary to integrate the desired functionality.

Contact Hyva experts or Magento experts who can help you deal with such situations.