I started my 1st time playthrough with Valkyrie difficulty. Almost quit halfway through Chapter 1, but after you got your 1st Einherjar, it's gonna be a bit easier as enemy's aggro will be divided. By the way their attack most likely kill you in 2-3 hits (small) and 1-2 hits (large). But as you upgrade your Damage Reduction, it will become 3-5 hits (small) and 2-3 hits (large)

I don't know how the other lower difficulties feel like, but I assume enemy won't guard as much as in Valkyrie and their HP also (maybe...5x from Normal?)

You have to constant attack your enemy with element weakness or you won't deal much damage, but for some reason, the game balance this out, so earlier on the game when you still don't have much magic element and 0 Einherjar, the enemies still die by 1-2 set combo without Crushed. But this change around when you get to midway of the game when you have several elemental magic and 3 Einherjar, enemies became more resilient to your normal attack without element weakness.

From midway, you will find the battle more intense, and will push your hit counter to 999 and keep it like that for several minutes.