Tl;dr: Dialer is not trying to connect to Google, it was microg
Although the /e team changed some? aspect of the dialer app, Google seems stil sitting anywhere inside and is serving some purpose for Google (or the user who wants / need this ;- )
I installed a Samsung S5+ e-0.22-p-20220213163416-dev-kccat6 and setup the included SIP VoIp client (SIPAUA/0.1.001) and probably this app tries to connect mtalk.google.com
Some more info
Addendum: Perhaps not connected to this app but initiated from MicroG, there ist a configuration option to disable device registration / google cloud messaging. Some effects associated with it
Add2: Also with disabled Google device registration & disabled Google Cloud mesaging the phone still want to contact mtalk .google .com. Interestingly: Google SafetyNet ++cannot++ be disabled! possible, but microg uses its on logic ;- )