I recently purchased the Bonavita as well. After years of using basic automatic drip coffee makers this was an adjustment. I still haven't perfected the art of the cup using the Bonavita. The problem is that the Bonavita brews at the correct temperature, so I think you really need to be a little more precise when brewing (at least that's what I discovered).
First of all, the Bonavita brews only 8 cups--and each cup is only 5 oz. I use a scale to get as close as I can to the correct water-coffee ratio. I no longer use a scoop: a scale is the way to go.
I have found that with the Bonavita a medium course grind is best. I also found that lighter roasts are less likely to produce the bitter flavor you are experiencing.
I usually brew at a water ratio of 1:14. So that means that I use about 84 grams of coffee for a full pot. I know, seems like a lot of coffee. i never used that much with my Mr. Coffee. But, once you figure out the correct grind and amount, the Bonavita produces a great cup of coffee.
Go to https://baristahustle.com/the-coffee-compass/ and read the article. The "Coffee Compass" really helped me out in trying to get that great cup. Just the other day, I ground up some coffee at a slightly higher setting and the coffee was weak. So now, using that setting, I had to up the amount of coffee by a couple of grams and it was perfect. And that was thanks to the Coffee Compass.
It is so trial and error, I have to say.
Here are the basic ratios to use with the Bonavita. I have found that the 1:14 produces the better cup in my opinion. Also, lighter roasts tend to not be as bitter as the darker roasts.
Bonavita cup = 5 oz. (147.87 grams = 1 Bonavita cup or 29.574 grams an
ounce) Each cup = 5.215 ounces
4 Bonavita Cups = 20 oz = 591.47 g (Ratios: 1:14=42 g; 1:15=39 g;
1:16=37 g) Note: Finer grind
5 Bonavita Cups = 25 oz = 739.33 g (Ratios: 1:14=53 g; 1:15=49 g; 1:16=46 g)
6 Bonavita Cups = 30 oz = 887.20 g (Ratios: 1:14=63 g; 1:15=59 g; 1:16=55.45 g) Note: Medium grind
8 Bonavita Cups = 40 oz =1182.94 g (Ratios: 1:14=84.5 g; 1:15=79 g; 1:16=74 g) Note: Courser grind
Hope this helps. Happy brewing.