Win addict Loss addict

1. Win addict/ Loss addict

Do you say those words like "he is a win addict", "he is a loss addict"?
Should I say "he is addicted to winning"?

2. He is learning/learns a lot through/by working here.

Do both through and by sound natural in the sentence?

Thank you in advance!

Question

Win addict Loss addict
 
1. Win addict/ Loss addict

Do you say those words like "he is a win addict", "he is a loss addict"?
Should I say "he is addicted to winning"?

2. He is learning/learns a lot through/by working here.

Do both through and by sound natural in the sentence?

Thank you in advance!

Answer

1. It is more natural to say "He is addicted to winning".

2. "He's learning a lot working here". Present continuous sounds more natural from those choices.

Though I would personally use the present perfect tense here: "He has learned a lot working here".
 
"The present perfect tense is one of the common verb tenses in English, used to show an action that happened in the past that is directly related to the present, such as actions that are still continuing or that indicate a change over time."

Furthermore a preposition is not necessary in this sentence:)