Rewards decreasing

It’s been one year now i’m using Brave on my laptop and my phone. Everything was perfect. But I noticed that I continue to see lot of ads per day (I’m working as Developer so everyday in front of screens) but it’s seems like the rewards are not in consistency. It was like +15 Bat per month now it’s just 2 ~ 4. Can you check it please or maybe I have to do an extra configuration?