It appears that coffee drinking (3 to 4 cups/day) is associated with both lower risks for heart disease and total mortality, at least in Italians. This means that it is OK to drink that much coffee per day and not risk cardiovascular disease. In other words, it can definitely be part of a healthy diet. Other countries may have already found this out (don't know) but it seems that the Italians have finally found it out. It may be because we (I'm Italian) can be kind of slow when it comes to certain things but we get there sooner or later.
https://academic.oup.com/jn/article/151/2/395/6056516