I bought these running boards and mud guards for the third generation Toyota tundras off of Amazon for less than half the price of OEM versions. I am extremely happy with the quality of both so far and the links are below:

Side Steps / Running Boards: APS iBoard Running Boards 5 inches Matte Black Compatible with Toyota Tundra 20222023 CrewMax (Nerf Bars Side Steps Side Bars) https://a.co/d/iIWraYN

Mud Guards: 4 PCS Mud Flaps for Toyota Tundra 2022 2023, Toyota Tundra Mud Flaps Splash Guards Tire Protector, No Drilling Required Mudguard Included Bolts https://a.co/d/4lBkfZP