I developed multi-ssh, it's a command-line utility designed to simplify the management of simultaneous SSH connections to multiple remote servers. It leverages tmux to create organized sessions, allowing you to interact with servers in separate panes within a single window or in individual windows per server. Features include synchronized input across panes, executing commands on all servers, copying files using rsync, and customizable configurations via a config file.

https://github.com/arakis/multi-ssh

Thank you for this. I’ve been baffled by how many of the usual tools are a poor fit for persisting work over SSH across multiple servers.