I mis understood, sms is pretty much history over here, so I considered you where looking for some way of sending messages to your phone.
Pushover supports a simple api, which can be used with curl. A la: https://support.pushover.net/i44-example-code-and-pushover-libraries#unix
Does https://pushover.net/ work for you? Been using it for several years, works really well and can be used in several applications.
Or some minor scripting with curl.
Esp32Cam with esphome running a webserver, add frigate in the mix and you can have dozens of cameras for just a few bucks.
Completely open source (apart from the espressif wifi radio stack, but who’s counting) and low cost.
Yes, quality of the camera will never compete with commercial stuff, but this is way more fun. Add as much cameras as your frigate instance allows…