From my experience managing this, you'll want to focus on your core class abilities through the whole game. When facing tougher enemies like Mind Flayers or boss encounters, watch their attack patterns carefully since you won't have those extra tadpole bonuses to fall back on. The main strategy revolves around positioning and resource management, especially during longer fights where those bonus actions could've helped.

The fight difficulty really ramps up in certain areas like the Shadow-Cursed Lands, so maybe interesting to keep some scrolls and potions ready as backup. Your companions' abilities become crucial here, particularly when dealing with multiple enemies that those Illithid crowd control powers would've helped manage. Playing on Tactician definitely needs more planning, but the game gives you plenty of tools through standard spells and abilities to handle everything thrown at you. Just remember to use height advantage and environmental hazards more since you're working with a more limited tactical toolkit