[Q] Is it appropriate to use Cronbach’s alpha when I have more than one variable in a survey?

Hello! I’m planning to use Cronbach’s alpha on a survey’s results, but want to know if it’s possible to apply it in this case.

The survey has 25 questions. There are 5 questions for each variable being measured.

Would I have to apply Cronbach’s alpha on the 25 questions as a whole, or should I apply it separately for every variable .

From what I can understand, Cronbach’s alpha measures the correlation between the results, so if 2 questions have similar results, Cronbach’s alpha will be higher . However, one cannot necessarily expect the results of different variables to be similar. In other words, questions from different variables will be measuring different things, resulting in an unacceptable Cronbach’s alpha.

Extra info if it matters: I’m using a Likert’s scale . There are 5 variables, one of them is the dependent variable in a multiple linear regression model, the other 4 variables being the indepentend variables.