many mobile carriers allow sending texts via email (for example: 3048675309@vtext.com with a verizon number), which might be worth looking into should you want to avoid twilio completely.
https://www.smseagle.eu/2025/05/08/no-support-for-email-to-t...
I had a filter in Gmail that forwarded some emails and a cron script that checked the value from a river gauge and sent a text.