To start with I cut out refined sugar and followed the standard NHS/NICE 'Eat well Plate" and my BG did drop. But, after about 8 months I started seriously reducing carbohydrates and this reduced my BG further, and it's still steadily, though slowly, falling.
Carbohydrates in foods are converted to glucose during digestion, so you can still be ingesting 'sugars' even if you are thinking you are avoiding them. The 'sugars' on the 'traffic lights' on food packaging are not a good guide to how the food affects BG. You need to look at the carbohydrate content on the back of the packages.
You'll find many folk on here follow a LCHF (low carb, high fat diet), but we are all different and some folk can tolerate some foods better than others. It's all a process of trial and error until you learn what you can and can't eat, or perhaps what you should and shouldn't eat.