You could have an alternative to the helper mode, the 'dungeon master' mode. This player wouldn't have much, honestly, to do, if you wanted to have the same level of play. They could control ships that the human player shook loose as threat, choose bonus ship types, set general targets for waves, stalking forces. And get a bit bored, because they'd have a lot less opportunity to take the initiative.
I could see this taking the place of the former netflix mode (fallen spire shard chase). There's been days where I've been willing to host, but not as interested in providing the leadership to make sure my group makes any progress. Hosting, occasionally intervening, and watching TV would be great for everybody in my co-op group who isn't able to host themselves.
Malevolence is more fun than leadership, after all.