"To the nth degree" is a commonly used idiomatic expression that refers to the highest possible level or extent of something. This phrase can be replaced with many synonyms that carry the same connotation, such as "to the utmost," "to the max," "to the extreme," "to the limit," "to the highest degree," and "to the pinnacle."
Other synonyms that can be used include "completely," "absolutely," "utterly," "entirely," "fully," "thoroughly," "exceedingly," "intensely," "severely," and "profoundly." These words are often used to describe a feeling, situation, or experience that is intense or extreme. Using these synonyms can add more emphasis and depth of meaning to your speech or writing, making your message more impactful and memorable.