It took losing a six-hour migration to a dropped wifi connection before I finally took tmux seriously. The job was halfway through, the SSH session died, and so did the process attached to it. I had no one to blame but myself, because I had been told this exact thing a hundred times and ignored it.
The fix is embarrassingly small. SSH into the box, run tmux new -s work, do your thing inside. When the connection drops, the session keeps running on the server. Reconnect, type tmux attach -t work, and you are back exactly where you were, scrollback and all.
That is genuinely the whole trick. There is a deep world of panes and layouts and status bars underneath, and I do use some of it, but none of that is the point. The point is that the session lives on the machine, not in your fragile little terminal, so a flaky connection becomes an inconvenience rather than a disaster.
I keep one config line, set -g mouse on, so I can scroll and resize panes without remembering the keystrokes when my brain is full. Everything else I learned slowly and only when I needed it. Start with attach and detach. The rest can wait until you are no longer afraid of the network.