I’ve been drinking coffee since high school (coming up on my 40th reunion!). I like to joke that I’ll drink ANY white liquid in my coffee before I’ll drink it black, even paint.
I gave up any sweeteners in coffee a long time ago but what I cannot give up is cream of some type. If you are off sugar and sweeteners, you’ll notice just how sweet cream really is, so to me it takes off the bitter edge. Unfortunately, I can’t do cream either, because I’ve turned out to be very dairy intolerant, but coconut milk/cream works just the same for me. It has a natural sweetness that is just enough to take the bitter edge off coffee.
Brewing method makes a difference too. We use a paper cone type filter (Melita style), and IMHO it holds back some of the bitter compounds in coffee differently than a French Press or percolator type brewing system does.
I had to wean myself off sweetener in my coffee. I started by reducing it by half, then half again, until I no longer needed it.