I chatted with Astra about this ask here: https://chatgpt.com/share/6ac42567-c404-83e8-b8fe-d29040f451...
I flip on and off using my own term-preserver toolkit, which let's me autoreconnect to servers (via ssh) and or tmux sessions automatically. https://tangled.org/jauntywunderkind.bsky.social/term-preser... . There's a variety of others like this, zmx, zmosh, https://github.com/neurosnap/zmx https://github.com/mmonad/zmosh
Sharing one SSP connection across several terminals is a big protocol change, and I'm deliberately keeping mosh-rs wire-compatible with upstream, so I don't want to go off on my own there. For "lots of tabs, one connection" the thing that works well is one mosh session into tmux, and tmux control mode (tmux -CC) if your terminal supports it. That gives you native tabs over a single mosh link, which is about as close to ControlMaster as you can get with mosh's design.
In Mosh, there is no native Windows client (you run it inside WSL), and there is no scrollback, which is the most-upvoted open issue on the project since 2012. mosh-rs has both.
I would especially like to hear from people who use mosh over bad links or on Windows. Any feedback/testing is appreciated