> The downside is that V2 doesn’t support all the controllers that were implemented for cgroups V1 (e.g. devices, net_cls, net_prio,etc.).

device controller is present since kernel 4.15.

> Adoption status

Docker/Moby supports FUSE-OverlayFS and cgroup2 as well on master. Planned to be released as v20.0X.

> spearheaded by Podman and LXC.

Yes w.r.t. cgroup, but the network stuffs (slirp4netns & RootlessKit) were originally written for Docker/Moby :)

> the truth is that container engines run Slirp without the seccomp support

Untrue. https://github.com/containers/libpod/blob/d4a3c05c0fcd0c53fa... https://github.com/moby/moby/blob/b47e74255811b2ead92b222541...