Are nasolabial fold fillers effective?

Lately, every time I look in the mirror, it bothers me because my nasolabial folds seem to be getting deeper.

It stands out even more when I smile, and it makes me feel like I look older, so it's stressful.

So I'm considering getting fillers. What is the actual satisfaction level regarding their effectiveness?

I'm also curious if it fills in naturally and if it might look unnatural.

I would also like to take into account if you could honestly tell me about the duration of the effect, side effects, and the recurrence of sagging.