I've tried these but I need MMSes and can't figure out the alpha one with MMS.
I have a pinephone and found an okay one here. https://wiki.pine64.org/wiki/PinePhone_MMS_with_Matrix#Set_up_MMS_bridge_service
It doesn't work very well but I can ssh into the pinephone and restart it or mess with the modem as needed. You run a matrix server and its a python script on the phone that bridges messages to it. I hate using my phone so its super easy to put up with. I do wish it was written better.... I've been considering either contributing to the project or making my own because it doesn't seem very active.
Edit, sorry, so, I forward my calls to a VoIP number and I bridge SMS/MMS using the pinephone to a selfhosted matrix server. Id love to bridge m'y calls to matrix too but I can't find anything that does that.