I used to have the smashy oxo chopper. For a beginner cook it is great. I found that it produces inconsistent sizes for anything besides "mince" so yeah, garlic works, or onions for salsa. Nowadays I would recommend taking a knife course (or at least some youtube studying) and using the chopping time as a break from thinking about work. Prep work can be cathartic, and even if time-consuming it is not time-sensitive.

Edit: realize my comment sounds negative about that chopper. while I don't use it anymore, it's cheap enough and worth trying if you are on the fence or don't enjoy the prepwork.