How to wait for element to disappear in cypress?

IMHO the cleanest way is not to use waits nor timeouts with get, this is kinda an antipattern.

I would recommend to use Cypress waitUntil command and use something like:

 cy.waitUntil(function() {
  return cy.get('element').should('not.exist');
 })

or depending on the app code you can use not.be.visible.