Here is the creative hook most players miss. Use the save editor to manipulate Renown and Bonds.

You tried to equip a weapon skin that doesn't exist for that character (e.g., giving Lu Bu's Sky Scorcher to Xiahou Dun). Fix: Only edit weapons that are already in the character's inventory. Do not change the "Model ID" field unless you know the hexadecimal codes.

If you are playing on PC (Steam), the process of using a save editor is relatively straightforward, though it requires attention to detail. Here is a step-by-step breakdown of how the workflow generally looks.

You want to play as Lu Bu and instantly flatten armies. But the game says: "No. First, fish for 30 minutes. Then, craft 200 iron ingots."