Any suggestions for running an SBC (Session Border Controller) for SIP/Voip

[hgerding]

Any suggestions for running an SBC (Session Border Controller) for SIP/VoIP on an Opnsense box

Looking for Packages and Pros/ Cons/ Risks

I need it for running SIP phones on the network to an external provider, and I am looking for an economical and open-source solution to this.

I need it for more than one solution, one is 3cx, but it will be something else when done (Client is moving to a different VoIP provider). (I have looked at the PI5 but prefer it on the OPNSense box)