Should I get 100% relief from acid reflux on Prilosec 40 mg dose?

Nope. Nothing is 100% in medicine. However, you can relieve your symptoms if taking the medicine properly. It's designed to be taken 30 min prior to the largest meal of the day. I usually tell my patients before the evening meal. Should be taken for only 3 months. If you still have problems after that time period, you may need a scope of your upper esophagus/stomach/duodenum. Aka egd.
No. Prilosec or any other ppis (protonix, nexium, prevacid, dexilant, (dexlansoprazole) aciphex) can suppress acid production significantly but never 100%.