There are high protein supplements with less sugar (well, other than meat, which is the simplest). Many substitute stevia or other artificial sweeteners, or sugar alcohols like maltitol. Sugar alcohols may cause intestinal gas and stomach upset in some folks. I avoid using those during exercise since the bloating and gas can be uncomfortable. I'll use Clif or Larabars, which use regular sugar.
Legume based protein bars can be gassy too. I prefer whey, just to avoid the gassy bloating.
But there's lots of protein in unsweetened Greek yogurt, Icelandic skyr, and it takes only a little honey or some bananas to make them palatable for folks who prefer a little sweetness in stuff like that. Siggi's Icelandic skyr is tasty, even better than Greek yogurt. I add it to oatmeal, or use it instead of sour cream on baked potatoes.
Whey protein is very cheap, so the only reason to pay more for name brand supplements is the flavor and texture. There is a difference between the many brands. But mixing your own protein shakes is much less expensive than buying premixed liquid supplements. Since the powders are relatively cheap, buy the stuff that tastes good. You're more likely to actually use it. I've thrown away or given away some bad tasting protein powders, especially the stuff made from legumes. I just can't get along with protein powders made from beans and peas.