Contrary to what the majority of people think, your taste buds have *NOTHING* to do with tasting your pv liquids other than sensing if it's sweet, sour, salty, bitter, or umami. It's your nose that actually tastes your liquids. Your nose will acclimate to constant smells over time (same way a dairy farmer no longer smells the cow poop around him, but you would immediately). Try eating your favorite food while pinching your nose closed. That's essentially when is happening with your fave liquid. The remedy is easy, switch off for a while to a liquid that is totally different than what you normally vape.
My dad is a big tobacco/coffee flavor fan, but found his selections lacking. Going up in voltage helped for a while but the result was the same. I told him try another flavor other than what he liked and don't switch off until that flavor dulls (in this case VB fire & ice, green apple, etc). After a month or two he went back to his daily vape of Boba and he said it was like Xmas day.