I drink a lot of milk for the protein it has. I don’t find it increases the mucus but I have been taking extract of Mullein and I couldn’t believe the difference it makes. My lungs are fluid rather then like a block of cement

Probably. IF you are already lactose intolerant. But there is no real proof that lactose contributes more to mucus levels any where, especially in the lungs. A version of lactose is used to make many pill medications too. The truth is mucus exists throughout the body in varying amounts - all the time. For this, staying hydrated with water, teas and juices helps the most throughout the day. Take a look at this:
https://www.healthline.com/health/lactose-intol...

For me, One glass of milk has most of the calcium and Vitamin D needed daily. Helps with soothing the stomach for some of the med pills I take too. Strawberry is my favorite flavor! be Well.

Everything You Need to Know About Lactose Intolerance

https://www.healthline.com/health/lactose-intolerance

I use almond milk! Never gave it a thought 🤔