What your seeing is interveinal chlorosis. Essentially it’s a nutrient deficiency causing the yellowing of your leaves in between the veins. You’ll need to identify if it’s older leaves or newer leaves dying first. If older, it’s likely manganese or magnesium. If it’s younger leaves, it’s likely iron.

It’s worth noting that you also have necrosis around the outsidea of the leaf as well which is typically a sign of other deficiencies as well.

The easy fix is to just give your plant a little fertilizer. Should start to help after awhile. Your going to unfortunately lose those leaves though.

Thank you for this very scientific answer.

I think it might have started with younger/small leaves, some of them became fully yellow.

But only the older ones have the necrosis.

There was a lack of water during hollyday, then too much water to compensate. But it started showing small signs before that. I’ll try the fertilizer