Battery life fluctuating

Hi, I own a Razer Blade Advanced 2019 8750h 2080 Max-q It is the smallest most powerful laptop i have used(never going back to Alienware) One of the reasons i love this laptop is the close to 7hrs battery life on daily usage(no intense operations). I had no issues for the last 2 years except now when i have an issue. Since 2 weeks back my laptop battery life has been fluctuating, I sometime get 60mins -90mins of battery life and sometime I get close to 6 hours. I would be grateful if someone could help. I am not mug when it comes to laptop , confident enough to dismantle and assemble the whole laptop(did it once). So if someone can help or point be in the right direction it would amazing. Thanks in advance. Cheers!