But it's clear that your goal is to reboot on-prem servers through your phone. Something I've wanted to do with rundeck and a very simple web app that uses the rundeck API.
I'm using ansible right now, and a custom playbook.sh script for some sort of auditing - what was run where and by whom. Kinda works but much more maintenable than let's say ansible tower.
Should be very possible though, Rundeck has Ansible integration and with Ansible playbooks you do anything.
So all your custom website has to do is provide buttons for those pre-defined Ansible playbooks in rundeck.
I can email my house, which is at least encrypted in transit, and then I stack an extra couple nonstandard abuses of email headers to validate the source, which all is impossible with SMS.