not ready for prime time 

The term to describe one who lacks the necessary level of knowledge,
skill and experience to be considered in the league of experts in a particular field...

The candidate's poor performance in the debate made it clear he/she was

not ready for prime time.

not ready for prime time by sheila in the car June 18, 2013

Not ready for prime time 

A new yet untested piece of technology that's currently not ready to replace anything related to the industrial revolution and therefore not ready for mass consumption.

Ev's are not ready for prime time and won't be for another 2 or 3 decades.

Not ready for prime time by Uncle Dimma July 20, 2022