Are coffee cores allowed?

So, friends! Today I decided to tell you about the benefits of coffee and! Yes Yes! Gone are the days when doctors categorically forbade patients with any heart problems to drink coffee.
For many years, scientists have studied coffee and came to the following conclusions:

Habitual coffee consumption has been shown to be associated with a significantly lower risk of developing type 2 diabetes.
Also, drinking coffee is associated with a decrease in the risk of death from various causes (cardiovascular, respiratory diseases, stroke, while not affecting in any way the number of deaths from oncological pathologies)
Several studies suggest that coffee consumption is not associated with an increased risk of hypertension. However, a short-term rise in pressure can still be noted after drinking coffee. Therefore, you should refrain from using it at an initially high blood pressure (more than 140/90 mm Hg).
As for the effect of caffeine on arrhythmias, there is a number of studies confirming that caffeine does not affect the development of atrial fibrillation, as well as ventricular rhythm disturbances. Some studies have indicated that drinking coffee even reduced the occurrence of atrial fibrillation by 6-13%. However, this issue requires further study.
And the cherry on the cake will be a study by German scientists!
They concluded that a daily dose of caffeine can have a beneficial effect on the activity of heart cells and their ability to recover from myocardial infarction, as well as protect against diabetes.

But how much caffeine does it take to show its cardioprotective properties?
It turned out that its optimal concentration in the blood is 30 μM per liter, equivalent to four cups of coffee. It should be clarified that we are talking about filtered coffee.