Looking for advice on my Fiddle Leaf Fig’s crispy leaf edges

Hi everyone,

I’ve had these two Fiddle Leaf Figs for a few years now. Overall, they’re doing quite well and regularly grow new leaves. However, I’ve noticed that the edges of the leaves don’t look very healthy—they are a bit "cracked" and look dry.

What can I do to improve this? I’ve already tried placing a humidifier nearby, but it didn't seem to make much of a difference and it’s quite a hassle to maintain.

I water them regularly using self-watering pots (with a reservoir). Sometimes the reservoir stays empty for a few days before I refill it—could this be the cause?

Thanks in advance for your help!