Between runs you have to write the last used number to a fixture,

And("I enter a name", () => {
  cy.fixture('name-num.json').then(num => 
     const next = num +1;
     portalPage.roleName().type(`Cypress admin ${next}`, { force: true })
     cy.writeFile('cypress/fixtures/name-num.json', next.toString())
})

If you do this multiple times in the same run, cy.fixture won't work because it caches the value it reads.

Instead use readFile()

And("I enter a name", () => {
  cy.readFile('cypress/fixtures/name-num.json').then(num => 
     const next = num +1;
     portalPage.roleName().type(`Cypress admin ${next}`, { force: true })
     cy.writeFile('cypress/fixtures/name-num.json', next.toString())
})

If you are seeking random inputs, then lodash .random() will generate a random number from 0 to the input.

// will generate random number between 0 and 9999
portalPage.roleName().type(`Cypress admin${Cypress._.random(9999)}`, { force: true })

If you only needed the values to be different within the same spec, you could store the value in a Cypress environment variable. The environment variable will not be cleared until the spec has finished running.

And("I enter a name", () => {
     // set the environment variable to current value + 1, or if it hasn't been set, 1.
     Cypress.env("myNumber", Cypress.env("myNumber")++ ?? 1);
     // use the environment variable
     portalPage.roleName().type("Cypress admin" + Cypress.env("myNumber"), { force: true });
})