While complex username/password + TOTP requirement is a standard and solid security requirement for administrative access to the SimpleMDM controls, it could be made even stronger with the addition of IP allow listing. I would love to have +1 layer of opt-in friction between the internet at large and a tool has the ability to brick all of my organization's laptops simultaneously.
If implemented, I'd request that a minimum of 2, preferably 3 remote sources be required before the service could be enabled: this will provide small businesses with redundancy for the event that they change ISPs and cannot bring their IP space with them