Awesome! Thank you for posting that update @Garshwartz.
I'm not sure what you mean by "pseudo dual active".
Can you confirm if you purchased the phone from Optus or elsewhere? I'm trying to figure out if the firmware has to be from Optus for VoLTE to work.
I'm very keen to know what options the dual SIM version has. I purchased my Mate 20 Pro through Optus and have no VoLTE options in any menu plus have no reason to believe the call quality is any better than a normal landline .The Optus website does not provide any positive reasoning to believe that VoLTE will work but if it's possible through a dual SIM version, I'm really interested to know why.