LuCI Missing Switch (DSA)

Yes, network works fine. That is about trying to get things working for stuff currently in the pipe as per ML. You can add the PR link by hnyman, but I suspect it is not quite what you may be imagining for DSA support as it currently arrives OOTB.

If trying to keep a partition at 19.x and one on master, you will probably have to backup and restore configs, after flashing without keeping config.