Whisk the mayonnaise, apple cider vinegar, and monk fruit or erythritol in a small bowl until smooth, then set the dressing aside. The mixture should look creamy and uniform, with no dry sweetener sitting around the edge of the bowl.

Place the chopped broccoli, chopped bacon, diced red onion, shredded cheddar cheese, and sunflower seeds in a large bowl, then gently combine them. Each scoop should show a balanced mix of green florets, cheddar, bacon, onion, and seeds.

Pour in the dressing and toss until the ingredients are coated, then chill for 1+ hours before serving. The broccoli will take on the tangy dressing flavor while still giving a noticeable crunch.