Battery life dies quickly and restarts/shuts off randomly

My iPhone 8's battery recently died. My battery health is 74%. My battery restarted at 50% and 100% two different times. After restarting, when it reaches the lock screen, the iPhone turns off and repeatedly does this so cannot enter the password in my lock screen. When I connect the charger to the iPhone it stops turning off and on.

Also my iPhone drain battery very quickly, skipping numbers like going from 67& to 65% battery, My iPhone can go from 100% to 50% in like 20 to 30 minutes of usage. It does charge faster(skipping numbers like opposite to it draining battery) than in the past but it's quick battery life makes using the phone hard.