So according to this

https://archives.gentoo.org/gentoo-project/message/5bb2e3ac0a30cb078a77898f6d5cdbcd

the hardened-kernel development will stop.

Hardened-sources is part of the hardening where the other part is toolchain and executable hardening.

There seems to be https://github.com/minipli/linux-unofficial_grsec but no new features will be incorporated only backporting if I understand it correctly.

We could contact https://grsecurity.net/purchase.php and ask if it would be possible to get the patches.