lvm2-2.03.14 introduced VDO (Virtual Disk Optimizer) support. Introducing a new use flag to pass --with-vdo=none|internal configure switch.
https://github.com/gentoo/gentoo/pull/25936 fixes this issue.
*** Bug 743986 has been marked as a duplicate of this bug. ***
Somebody needs to package dm-vdo first.
I have some stale vdo ebuilds which I use, fancy another pull request? VDO is split in two parts: kvdo - kernel module(s) and vdo - userland utilities Which one are you interested in here?
Kernel part (kvdo) has been merged into mainline for 6.9: https://www.phoronix.com/news/DM-VDO-Merged-Linux-6.9 So the userspace part (and maybe a change to sys-fs/lvm2 to optionally depend on it and >=virtual-sources-SomeVersion) would be the only things missing.