After reading first couple of paragraph of this paper, Wireguard (<a href="https://www.wireguard.com" rel="nofollow">https://www.wireguard.com</a>) comes to mind.
Then, they mentioned a research OS called Ethos (which seems to be defunct now).
Did they figure out a more mainstream implementation?
I found this[0] implementation that does not require replacing the entire OS with Ethos, but I haven't yet tried it and cannot vouch for it.<p>[0] <a href="https://github.com/nimbus-network/minimalt" rel="nofollow">https://github.com/nimbus-network/minimalt</a>