brent
Tried removing and adding the repo again, tried building database again, still says no packages to update.
And it's correct as I am already up to date. Reading the post initially I thought we were getting Plasma 6.4.2 but it's still in testing. My mistake for reading the post incorrectly. I also forgot when I updated my system but I must have done it without realising it. Anyway, sorry for wasting your time and thank you for the replies.