Depending on when and where the toilet actually gets made, they can source a variety of fill/flush valves in any particular toilet model. Mine have the Toto branded Korky Quietfill valves in them, and the actual fill process seems very quiet. So, maybe a picture of what's in yours would help. It may be normal with that fill valve. NOte, some of the noise will vary depending on your water pressure. Generally, you leave the shutoff at the wall fully opened, but you can at least adjust the volume (not ultimate pressure) down a little to see if that makes any difference. In most cases, it isn't a big deal if it takes a few more seconds refilling the tank and bowl if you shut the valve down some. Less volume, less energy, often, less noise. To keep the fast refill may require a different valve in the toilet. It doesn't cost anything to turn that valve down a little to see if it helps.