Interesting, I'm dying quite regularly, but I also feel like I still don't get the deflect system properly. I died to each boss, minimum 3 times, maximum 15 on the first one. Which weapon are you using? Do you consider yourself a player with great reflexes?
If you get hit a lot, then you might as well pump earth stat and use heavier armor. Better armor and more HP allows you to stay in the game longer and learn from your mistakes. You can get B agility (sub 70% equip load) wearing heavier armor at about 30-35 in earth stat. Earth is also a great weapon scaling stat, you got options for all these weapons: Spears, Halberds, Great Clubs, Pole Axes, Dual swords, 1h sword (I think one of them has high earth scaling?) - there's variants of those types that have earth as the highest scaling stat. For blocking, bigger weapons are typically better, you can check spirit defense on guard, and the higher the number the better it is for blocking. This is especially important if you're having trouble deflecting.
I got hit a bunch in the boss fight with clones, but I still won on my first attempt because I played smart. I didn't take a lot of damage from individual hits, and I could get HP back by using the HP leech buff before I used a finisher. I turned the clones into HP leech pinatas. It felt like I barely scraped a win, but I still had 2 pots left. Lu Bu only took 2 attempts, I did good the first attempt, deflected every leaping red he did on me, but he made me eat a dick with his big combo attack. 2nd attempt, he never got the chance to use it, the difference was me using pole axe instead of dual blades, which did a lot more HP damage, and spirit damage.
At this point, I got 40/10 earth/wood, the other stats are 1. I might spec fire enough to use the damage buff at some point, but I already got power up on martial arts hit modded onto my axe, and damage amplification on martial arts hit modded onto my dual swords. Start a combo with dual blades, and swap to axe, and your target has a defense debuff while you get a damage buff. Lu Bu would have went a lot faster if I had those mods on my weapons the first time. I don't know what the %s are for any of these buffs or debuffs, or if they stack or not with the wizardry buffs, or if they're basically the same thing, etc. And I'm way too lazy to test it.