I upgrade my Samsung unlocked on Verizon every year for 5+ years now, never had a problem. I do use a 3rd party voicemail app but the Samsung Voicemail app works fine as well.
Nope and as a matter of fact, I'm running Tmo on the e-sim as well on a 90 day network pass Tmo gave me. Mobile data prioritizes on which sim you make primary. Great fun as I flip back and forth comparing networks.
Actually having a Verizon branded device with Verizon firmware takes away features. Find My Mobile and Call and Text on Other Devices are not on Verizon branded devices with Verizon firmware. I found that out when I had a Verizon branded S10+.
This always bugs me about Verizon and using unlocked phones. Both of these phones are unlocked. One is from Verizon the other from BestBuy. Verizon knows what phone it is because it has the IMEI and all the details in another screen. So how hard would it be to list show the phone image instead of a blank shape?