[Xaena]

In a past life as a solutions engineer at a SaaS company, I'll address a couple points specific to a unified solution.

Problem 1: Not every SaaS platform has a company with an API to manage user accounts. Even then, I would be skeptical of a company that offered it and didn't offer it via oauth tokens.

Problem 2: Automating the task within the browser also fails when it comes to uniformity. Any company that lacks an API endpoint for user management means you need to interact with a browser or some other hacky nonsense. With that solution comes the problem of understanding the site structure, login forms, and action menus.

Problem 3: Even if you did the above 2, you now have additional points of failure within your offboarding. If a failure occurs in the automation process, is it silent? What if the API changes (not that it should) or the UI?

The best solution is to look for companies that offer the API option or that support SAML.