A word/idiom to describe someone who is impressive by speech but lack of experience in real world applications? (without negative connotation)

Someone who is articulate and able to sound impressive by theories or speech but do not have sufficient experience in real world applications. The word/idiom that I am looking for is without negative connotation. Phrases like "is all talk" and "look good on paper" have a sarcastic tone which I want to avoid.

The scenario I have in mind is someone who has graduated from a course that is relatively new to the market. There isn't a great demand in the market for such expertise yet. The person can only accumulate knowledge by research. They are able to convey impressively by theory. However, they do not have enough experience in real world applications yet.

Much thanks!

The person can be described as an academic in the sense that their knowledge and research are not connected (at least yet) to real world situations.

I would say that at this stage they are promising:

full of promise : likely to succeed or to yield good results e.g. a promising new medicine

It can equally apply to an individual, who is looking to prove themselves in the real world.

There is a popular expression that seems close to what you are looking for. We often hear of people who:

Talk the talk but don't walk the walk

You could adapt this and speak of a young person who

has learned to talk the talk but has not learned to walk the walk.