How to Find element inside iframe by its text in cypress

I’m trying to locate an element within an iframe based on its text using Cypress

Neither of the following methods is not working in order to find or interact with element based on its text:

`

import "cypress-iframe";

cy.iframe('[data-testid="iframe"]').within(() => {
cy.contains('The cost is £500.00.', { timeout: 30000 }).should('be.visible');
});

cy.iframe().contains('The cost is £500.00')
cy.iframe().find('The cost is £500.00')`