I don't think SSH vs OpenTofu is the core issue here.
For agents, declarative plans are still valuable because they are reviewable. The interesting question is whether exe.dev changes the primitive: resource pools for many isolated VM-like processes, or just nicer VPS provisioning.
https://github.com/hetzneronline/community-content/blob/mast...
It also has a CLI, hcloud. Am I getting any value with exe.dev I couldn't get with an 80 line hcloud wrapper?