There are many substances that surpass sugar in terms of sweetness. You have probably heard of aspartame (which is harmful because of its potential to cause cancer, and which I have seen in refined breads), sucralose, thaumatin or neotame, which is much more potent than aspartame and does not cause cancer or anything like that, and in fact it is used in some foods.
However, the sweetest substance on the planet is Lugduname, which is between 230,000 and 300,000 times sweeter than sucrose (the white sugar of all time). Although it would really take very little (but seriously, very little) amount of Lugduname to satisfy the required amounts of common sugar or other compounds, nothing is known about its effects on health. One of the most disturbing aspects is that it has chemical groups in its structure that are toxic on their own, such as its nitrile groups.
Tkach et al. 2024. Theoretical Description for Lugduname and PerillartinElectrochemical Determination by Cathodic Route.