Dynamic-sources availability is inferred automatically developers cannot dictate it explicitly.
For some metafield types + setting types there may be no dynamic-source interoperation.
In those situations using a liquid setting to output a metafield as liquid logic is the main workaround, i.e. {{ product.metafield.namespace.key.value }}
If you need this customization then contact me for services
Contact info in forum signature.
ALWAYS please provide context, examples: store url, theme name, post url(s) , or any further detail in ALL correspondence.