Seems like you are on of the lucky ones. I spent almost 4 hours chasing down this function. Verizon can enable advanced calling/VoLTE and WiFI calling. But the ability to enable is missing from my phone. THere isn't even an option to enable VoLTE, and WiFi calling is greyed out. Visiual Voicmail works... but thats it. Verizon told me you have to have their build on the phone to have those features.
i bought a unlocked s10e today .... inserted my verizon sim... volte worked immedietly.
visual voicemail did not. there was no app for it. nothing installed. i searched for the app in the samsung store and there was nothing.
samsung phone tech told me the unlocked version does NOT have visual voicemail with verizon.
The unlocked S10 does have visual voicemail with Verizon. It should download automatically from the Galaxy store, not the Google play store. Here is the direct link:
VoLTE can be turned on/off (it should be on by default) by going to settings - connections -mobile networks - VoLTE calls.
The wifi calling was giving me trouble too as the option was greyed out but I finally got it working. First put the phone in airplane mode and then turn on wifi. Go to the Phone app, tap the 3 dots in the top right and then settings. Now the wifi calling option should be unlocked.