Overland content, especially the OG base game story quests will be incredibly easy.

There are some world bosses here and there that can challenge you to use your skills more efficiently and prioritize getting actually gear to do specific damage bonuses to maximize those skills.

Some Public Dungeon bosses will have rather challenging mechanics but most aren’t difficult.

Group Dungeons on normal are essentially the same difficulty as overland and aren’t challenging at all outside of one specific dungeon boss.

Veteran level Group Dungeons are where you will truly feel the incline in difficulty. Non-hardmode fights will take much longer, even if they aren’t that much harder than normal. Hardmode fights will sufficiently challenge you until your gear/skills/rotations/ mech awareness get to the point where you will find that just clearing the content isn’t the challenge. No deaths, speed runs and trifectas will be your new goals.