What disease does my rubber tree have?

This rubber tree came into my care in a roundabout way about two years ago. It was most likely in a very dark corner of an apartment or even a basement. It's alive and showing new buds and a bit of growth. There's already a new leaf, but all of the leaves lack shine. Instead, the leaves have a rough, dull texture.

I wonder if it's mold, a nutrient deficiency, or an insect.

It could also be that there is something wrong with the roots, I haven't implemented it yet.

I would be very happy to receive ongoing ideas from you that would help me get my mind going a little.

(I just noticed a new leaf, it shines

the heating was used very rarely and at a low level this winter.