Just one advice that i can give is DON’T TURN THE MOUSE OFF, Instead let it sleep by itself even after you shutdown your pc. This is a known issue that most people are facing right now and you can also see that the red laser sensor light doesn’t go off even after switching off.
My battery life (I never swtich off my mouse) after letting it sleep automatically is close to razer’s claim of about 90 hours which is tested atleast 3 times after charging 0-100%.
You can also try another solution which is uninstalling your synapse completely, then letting your mouse go to 0% installing synapse again and then charge it back to 100%. Many people say that razer fixed it with a software update but people got it fixed by trying this method. So try your luck.