Is not condemning evil despite being able to do so, out of shyness, considered minor shirk, and is it among the major sins or minor sins, and is it on the same level as showing off?

A Muslim must denounce evil to the best of their ability, whether by hand, tongue, or heart. Praiseworthy modesty prevents committing indecencies, but it does not entail abandoning enjoining good and forbidding evil. "Abandoning an action for the sake of people is hypocrisy" means abandoning obedience for fear of what people will see, and this is hypocrisy. If a servant is unable to denounce evil due to weakness or fear, they should denounce it with their heart and avoid sitting in places where evil is committed, especially disbelief and mockery of Allah's verses.