They do if you enter an agreement with them for professional services; I'm not certain but I think there's an SLA also on their "managed" servers: https://www.hetzner.com/managed-server/
But the managed servers look comparable in price to AWS instances at the same specs? (I'm eyeballing, I don't want to pull numbers on my phone).
I don't want bare metal nodes, they put a high lower bound on the cost of a distributed cluster. I want a "herd" distributed across data centers, and a system that spins up new ones if the old ones die. I don't care if AWS shuts down an ec2 instance without warning, because a new one will automatically replace it.
They do if you enter an agreement with them for professional services; I'm not certain but I think there's an SLA also on their "managed" servers: https://www.hetzner.com/managed-server/
However, if you want a "no-human" SLA with bare-metal rented servers, I could recommend Gcore: https://gcore.com/hosting/dedicated
Their managed kubernetes even supports bare-metal nodes, which is actually something I'm using.