I want to just say one thing. I noticed some people use 'difficulty' as ticked to 'nerf x,y'.

You can complete game on tactician without:
- 'barrelmancy'
- minmaxing
- using speed potions
- using haste
- using fireball
- tavern brawler and any other feat or weirdo playstyle's
- multiclassing

It's possible, you can do this. But i recommend life domain cleric as hard support for this kind of run.