Top up the potting mix. After 2-3 years, potting mix becomes compacted and shrinks several cms. Old potting mix needs replacing after a while because of this “slumping” and also it becomes acidic over time.
Check if the soil has become hydrophobic.
Scratch the surface after you’ve initially watered to see if it has actually penetrated. If not, apply a soil wetting agent.
Indoor plants look good. Image, Real World Gardener
Check for pests or diseases: If you have any indoor plant problems is important to first diagnose what is exactly happening with the plant.
Is it just the soil, or is it something that needs spraying.
Because your plants are indoors I would recommend using organic sprays