Mine too were dry and brittle, although I didn’t have white spots on them. I started applying olive oil, the good stuff, at night time before bed. I put gloves on after. They improved a lot

Ive definitely heard in the past it could be some kind of deficiency in your diet or body. If its a big concern, it might be worthwhile speaking to your gp and seeing if theres anything to be alarmed over or things you could do to help

I used to get the white dots under my nails, I heard it was a sign of calcium deficiency but that could have just been a rumour. Definitely worth researching! I don’t get them anymore and I don’t even touch dairy so it was probably something else. Collagen supplements and healthy fats like salmon, avocado, nuts etc are all good for hair skin and nails

I find diet can really affect my nail growth and strength. If I’m having a healthy, balanced diet they grow nicely without those white dots. If you have a great diet already, maybe go to the GP like another comment suggests. I love Essie cuticle oil, maybe work that into your routine.

Is this something new or have they always been this way?
If its something new it might be a good idea to visit your GP for a general health screening and some advice on why this is happening.