System alerts / errors in B2B web design – How to design system alerts so that users pay attention to them

I need some support with one problem ? System messages in B2B web applications, specifically about them being ignored by users. Can you recommend any references or share your experience in designing them? System messages - I mean messages related to the operation of the system, namely:

information about errors in the database
information about upcoming deadlines
warning about unsaved user actions
information about the timeliness of data and the possibility of their supplementation

That is, partly about situations not resulting from the user action but from the system. The assumption is - message recognition, invasiveness in the scope acceptable by the user, creating the feeling of importance for safety and work in the system (but not to treat these messages as a buzzing disturbing fly) Thanks in advance for your help