I'm 22, would All-on-4 Dental implants be a good idea or should I get braces?

At age 22 I would recommend either invisalign, or if you simply don't have the patience, what I call instant orthodontics using veneers. However, to do proper veneers I recommend you have someone with a lot of experience do this as it is not a simple procedure in your case.

If your gums are healthy and you don't have any bone loss, your first choice should be to straighten your teeth with braces. Considering the extremely unlikely worst case scenario that you were to lose all of your teeth, I would still not make an All-on-4 treatment as one of your first choices because of how young you are. A consultation with an experienced surgeon and/or orthodontist could answer your questions more precisely.