I managed to change the switches and clean the scroll wheel of my mouse and it feels good again!
The switches were good during maybe 3 years and then began to fail. I managed to clean them with contact cleaner several times but it lasts shorter and shorter so I had to change them.
The scroll wheel I don't know why it would malfunction. I managed to clean it with iso alcohol and a toothbrush on the exposed mechanism.
It's a wireless Logitech G305, I really like it so I'm happy I can fix it!