Vodafone the other day put out something that said the same thing, calls due to covid and the leadup to covid were up over 70% overloading systems, Spark are having the same issue too I hear. So there is a really good chance that 2D are suffering the same fate or it will be happening while handed over to the other network depending on what network the other part is on.

Modern platforms like Whatsapp / MS Teams calls (and I assume Skype) are much better quality than PSTN.

I have just given up on a couple of recent voicecalls I have done. So bad its painful to listen to. Not normally this bad, but cellular voice is pretty crap most of the time, this is sounding like realvideo streaming over dialup in the early 2000s bad. Charlie brown adults have better vocalisation. Hate to think how half deaf people are getting on with the voice calls.

HD Voice has been supported on 2degrees for several years now. However the interconnects typically use lowest common denominator codecs so while you will get HD Voice between 2degrees customers, you may not if you are calling off-net. The number of HD-capable interconnects will increase over time.