That's pretty much exactly the issue. With a Lyla, her attack speed is significantly slower than a Rogue's. With that, Mysterious Beast might be another farm spot, as Lyla with Risk Life III can one shot the slimes
And then as I mentioned, you need multiple squads of Archers and Witches to deal with the air units.
I think while MB might yield more gold, it requires more work than deploying Betty, Prince at back and then AFKing for the rest of the map.