One option, go to your phone page for making calls and choose the settings in the top right and explore there. VoLTE uses 4G and 4G higher level options and data connections. . Prior to VoLTE calls were actually going through 3G, so one option is to go to Network options and lock to 3G and lower. This will slow down your internet but force phone connections back to 3G. 3G coverage is much wider than 4G. One reason for dropouts is your phone switching back and forth between 3G and a weak 4G signal, or 5G versus 4G. 5G has much worse coverage.
IIf 5G and is with Telstra there are different APN settings. Google "Telstra 5G APN settings" for these. Note the new settings should be 100% accurate and note on paper your existing settings so you can revert.
If you want to get a better idea as to whether coverage is the problem, load an app called Aus Phone Towers, in Play Store, and you can compare many things, 5G, 4G, closet tower, provider, etc.
By the way, if your phone and broadband are both with one of Telstra (and Boost), Vodafone or Optus, you should Google, for instance, "Telstra wi-fi calling" and implement that. This diverts your mobile calls to wi-fi if you are logged into a wi-fi network and your phone connection is weak. Well wortwhile, especially in your circumstances.
That is some of the worst advice I've heard yet in any forums I've searched on this issue (trying to disable VoLTE for Optus in my case)!!!!!
I had WiFi calling enabled from Optus by default without my knowledge and had nothing but issues. I'd walk more than 10m from the front door (walking to neighbours or getting in the car or even just watering the garden) and boom ... there goes the phone call.
Unfortunately NONE of our carriers correctly implemented this option and thus the moment you go beyond your WiFi's usable range you will loose your call.
If your internet service is xDSL still then FORGET IT!! Without a business class router with QoS pushing for VoIP services it'll never work properly.
If your children start downloading something heavy and you're on a slower connection then your call starts jittering.
Why would you help alleviate the towers and make the telco's job cheaper when you're paying top dollar for a service?
Oh BTW, my switching from 4G to 3G for calls (have bandpass installed to disable it since Optus were a bunch of 4 lettered words and removed the switch) actually doesn't cause any issues with my phone (Note10+ 5G) and the misso's (same model) is ex Helstra so doesn't have the bs lock anyway since only Optus are the 4 lettered pricks.
Horses for courses. I live near Canberra but far enough away to be part of a village which has terrible broadband/ internet service. For a number of users the ONLY way to receive phone calls is via wi-fi calling and, as part of a local Facebook group, this is confirmed by posters. 3G is good in the sense that the signal travels by far the longest distance., but it is being phased out. As you have stated, wi-fi calling works by choosing the better of two services, cell tower and wi-fi. Wi-fi is limited by wi-fi network range. The question is whether you still have cell phone access once you walk beyond the wi-fi signal and whether you still have connection via the tower. In our area many don't. VoLTE/4G is supposed to drop back to 3G when out of range, so your problems may relate more to a weak signal from the nearest tower. I suspect your analysis is flawed in that you may have incorrectly identified the wrong cause. To check this load the app called Aus Phone Towers and use the left menu to set for your carrier and specify 4G or 3G, etc.
