Google removed native SIP support on Android 12 and newer.
… most manufacturerers had removed their support respectively.
Here are some apps that have been tested with Android 13.
More Info about that topic here at xda-developers.
(If your manufacturer has not removed it from your ROM, and it supports SIP without any third party apps then you can skip the apps section below. You only need to configure SIP settings within your system.)
Please take a look for the general SIP Configuration hints before starting over with one of the clients below.
Here are the configuration steps for each app or recent non modified android version:
Have issues?
Please check if your input the correct password … again 
- Did you grant all permissions that where requires at fist run?
… if not reset to defaults and configure gain. - Power settings, beloved power settings…
Some manufactuers (e.g. Xiaomi) tend to use extreme power settings that kill apps after inactivity - check and if possible set less aggressive power settings for your SIP app.
not compatible
- SIP with Jami - no successful connection possible