I have to say on the flip side that our experience with Telstra when we were NBN'd earlier this year was EXCELLENT. We went for Telstra as at the time they were the only supplier that offered 4G mobile backup in the event of any hardline network issues and had a good bundle with phone, etc.... Optus now has introduced 4G backup I believe.
For us, the Telstra SmartModem2 with 4G backup arrived within a few days of the order and I set it up that day, changing over from TPG. Then a couple of days later the Telstra Contractor came in and installed the hard line in to the house from the pit in the street in about 1hour and we went from 4G
backup speeds of about 6Mbps to full speed for our plan some 51 Mbps.
They're OK in my book
I suspect the current difficulty lies with many people wanting faster NBN or just NBN with the soon to close other mediums/technologies. Couple that with everyone working form home and COVID, means a lot of new installs to do and the obvious OHS side of things and manpower issues hampering that. There are of course rural and remote areas with extra difficulties.
I hope all your issues get sorted guys.
Best
JA