Apologies in advance for mini-rant.
I’m obviously far in the minority, but I don’t feel this game is that difficult other than a couple specific fights. Some of the boss fights are tricky until you’ve learned them (which is how I feel boss fights should be), and there’s one or two optional fights in each act that are nasty. I need those fights because they’re the only fights in the game that let me test my builds and see if they actually work.
As for stealing, I don’t enjoy it and it’s not needed if you use the other economy tools. Get a character with high barter. Donate a bit of gold or make trades in the vendors favor to raise their disposition. With high barter and 100 disposition with the vendor you can now sell the stuff you either found with lucky charm or created via crafting for good money.
Use a bow, magic, or throw-away weapons to break down doors and open chests. There will be a couple chests you can’t get in to, that’s fine with me; it makes thievery feel like it was worth putting points in to. Just like I don’t get some quests if I don’t take Pet Pal and miss some stuff without persuasion.
By the end of act 1 you can have enough lockpicks to get you through the entire game with dozens to spare, sell the rest. You can make hundreds of poison, water, and slowdown arrows. Craft weapons to sell. Trade stuff for skill books rather than stealing them, it works fine.
You just can’t get every skill book immediately at level 2, but then which RPGs give you all your skills an hour into the game? Gotta have that constant drip or I’ll get bored and not finish unless your story is spectacular.