Is filler treatment the most effective solution for increasingly worsening nasolabial folds?

Lately, my nasolabial folds seem to be getting worse, so I'm considering getting a procedure. In the past, they were only slightly visible when I smiled, but recently, they are clearly visible even when I'm not smiling, and it's bothering me because my face looks older overall. In particular, even when I apply makeup, it settles into the lines or creates shadows, making them stand out even more.

I have heard that fillers are the most effective treatment for nasolabial folds, so I am considering getting them. I am wondering if deep-seated wrinkles can actually be naturally improved with fillers. I am also curious if there are limitations to what fillers can achieve if the cause of the wrinkles is not simply hollowness but rather skin sagging or a loss of volume.

If I were to get nasolabial fold fillers, I would like to know where and how the procedure is performed, as well as how long the effects typically last. I prefer a natural reduction of my nasolabial folds rather than an overly plump look; in this case, what procedure would be suitable? I would also appreciate it if you could let me know of any other procedures recommended for improving nasolabial folds besides fillers!