A word or phrase that describes a person who is a corporate employee with a very demanding work schedule, but keeps positive and optimistic

Recently, the word “打工人” has become a buzzword in China. It refers to a person who is a corporate employee – or anyone who works very hard only to earn a low or middle income – but who is still optimistic about life. That might sound weird, but it actually happens in China.

I hope to find a word or phrase to describe them. Thanks very much for your kindness and help.

Solution 1:

I cannot think of one word that covers your definition. There are two that almost do the job and, if taken together, cover it well.

Stakhanovite = An exceptionally hard-working or zealous person

Lexico

it may be an adjective: of or relating to a Stakhanovite or to Stakhanovism.

dictionary online

Pollyanna = a person characterized by irrepressible optimism and a tendency to find good in everything

Merriam Webster

Pollyannaism = blind or excessive optimism, after the character Pollyanna, created by American writer Eleanor Porter (1868-1920).

Free Dictionary

If I had to choose one of these it would be a Pollyanna, because the word certainly covers the unquestioning optimism, and the tendency "to find good in everything" would also apply to hard work. Or a Stakanovite Pollyanna would be such a person as you define.