I switched from tmux to Herdr about six weeks ago. It's a great bit of software, the UI is focused on switching between multiple agents quickly. I run Herdr to keep my opencode instances well managed, and it also works great for having a few terminals opens next to your agent. I find myself keeping opencode sessions open for longer like what happens with Codex and Claude code, which is great if I need to revisit a context to do some follow up work. I'm genuinely excited to see if the creators can bring even more value to the application.
If you're worried about enshittification I wouldn't be. It's relatively basic open source software that runs locally. A perfect candidate for a fork if the base app starts degrading.