Nice, I got the Plasma 6.5 update tonight.
Yes, it was released in October, but it's actually the latest point release at 6.5.4 which was released earlier this month.
People have this idea that if you're on Gentoo 
you're always with the bleeding edge, but that's an option if you go with the unstable ~amd64 tree. I'm on the stable amd64 tree (notice the lack of a tilde) and that's a bit more conservative.
You can even mix and match as desired by unmasking specific ~amd64 packages, but I rather keep that to a minimum as that isn't advised and can lead to unexpected behaviour.
Another thing many people don't know is that Gentoo actually defaults to binaries whenever it can. You only get to compile from source these days if you have a specific USE flag config or binaries aren't provided which, while exceedingly rare these days, is apparently the case for KDE Plasma (or maybe I have specific USE flags set and forgot) ... Oh well.
In any case, thanks for keeping up the work, dear Gentoo devs 馃挏