MacBook 2021 M1 Pro slower than older 2015 intel core i5 MacBook Pro

I have had my 2021 M1 Pro 14inch MacBook Pro since October/November. I find that the battery life and performance is far worse than my older 2015 intel core i5 MacBook Pro. The M1 Pro has 10cpu/16gpu model with 16GB ram and 1TB NVMe SSD. I started the M1 Pro with a fresh install and profile and transferred data/apps manually. I have reinstalled macOS and that does not fix the issue. Apple basically just says sorry if all you use is 3rd party apps then they cannot be of help since diagnostics comes out clean as always. My 2015 core i5 MacBook Pro has a core i5 with 8GB of RAM and a 512GB SSD. Has anyone else face this issue? My M1 Pro only gets 5-6 hours of battery life on light usage with low brightness and most apps closed. Any ideas on how to improve the performance and battery life?