Since theres newcomers now, I will give advice as someone who beat both games legitimately.
BS1 is easy, you just need to the Drake Sword. It has a fire AoE attack that pretty much carries you the entire game.
BS2 base game is easy so do whatever, but when you get to DLC3 the difficulty spikes. You WILL have to grind a bit if you wanna do it legit, but in my own experience I just got both my Attack and Speed to 9999. Having the max HP you can obviously helps as well, and having every weapon maxed out is recommended. I think you can randomly find weapons in the Chaos Dungeon chests, so just go there to grind and find weapons. If you want/need more HP, one of the swords maxed out has a skill that buffs your HP and defense, I think its knight sword or whatever, very useful skill. Also hourglass items are game changer. DLC2 and 3 are hard af but probably the most fun RPG Maker combat you will ever see.
Unicorn bitch and the very last boss were easily the worst bosses in my opinion.