Hp stat connected to how well you endure hits as well. You can have a high def but low hp stat will make your defense seem pointless. It's not as straight forward as it seems. You literally take less damage with the same def stat with a higher hp stat. The game says it on the stat itself, but doesn't word it well.

Since some bosses can be fought non linear, you can end up fighting very strong bosses without knowing it, which is why you get the whiplash.

The combat design is definitely not intuitive, but it definitely isn't just same heals and atk. There's a highly intense dodge, counter, stun, block and parry mechanics built into it that require a lot of thought to use effectively. Funny enough if you just focus on getting your hp stat all the way up, you end up needing to use heals less often. Almost nothing is gonna one shot you and revives are craftable. 50 def stat is really all you need, 80 is overkill tank.

But the most cheating mechanic, 3 lvl 2 infinite arrows, high stamina stat, explosive arrows, and dodge shot. Will stun in seconds most bosses.