No. Sacrilege. You can mix lesser drinks, never Rakia.
It is normally imbibed with a salad (pickles work great) or slanina/salo.
Also, yes, 40% is because it’s the mass consumption crap you can buy from the supermarket – least common denominator tastes. It’s supposed to make your tongue numb, that’s part of the deal. It’s not wine or beer that you’re supposed to quaff. Sip it with reverence.