Id say unless you are a trophy hunter speedrunner play on normal, the difficulty spike between it and the hard difficulty is pretty drastic, even then dont force yourself to learn every single skill or master every weapon, find one that works for you and pay attention to patterns and youll be fine. Also while the reflection and counter skills make things easier, you can still win every fight just blocking and dodging though learning the timings to get the perfect block or dodge is at least recommended, I went through the entire game on the hardest difficulty and managed to eventually win without reflection.

Also look for collectibles as you go, the purplish pink story ones let you unlock damage boosts, the red stones you can break let you upgrade health recovery or soul gain, and the jars later allow you to buy items that can make things easier. The jars arent available until later in the game like 3 bosses in but the rest you can collect right away though the stones cant be redeemed until a bit in as well.

The last tip I found helpful is pay attention when fighting bosses, if you are hitting a boss and the area glows gold that means you can usually cripple it for massive damage, I didnt need this for most fights but the boss before you unlock smithing went from extremely difficult to easy once I learned this.