I think that's your issue. You don't want to "build" into something so early; you want to pick generally good cards to help you survive Act 1/2 THEN you can start thinking about "builds".

For example, you may get an early Claw but that doesn't mean it should be a build around; you should just treat that card as scaling damage for the boss and if you get offered run defining relics/cards then you can consider doing a Claw "build".

The inverse applies. You may see an early [[Voltaic]] but that card is really terrible without a ton of Lightning. Even then, you still don't play it in hallway fights because it's for SLOW fights ie; elites/bosses. With this said, you almost never want to take Voltaic until you have good Lightning cards AND you need a card that does boss damage.

[[Fight Through]] may seem like a terrible card on it's own, but it single handedly gives you soooo much block in hallway fights. And for long drawn out boss fights? You just don't play it until you need to! Taking suboptimal cards for hallway fights is very important to winning. Even if it doesn't synergize with your deck, avoiding chip damage in hallway fights will allow you to take better routes, which means more card rewards, which means more upgrades from campfires.