MacBook Pro (Retina, 13-inch, Early 2015) 250GB available of 1TB . Installed Big Sur 4 days ago and since then overheating and fan running more often a process named Kernelmanagerd using CPU between 60 to 70% battery draining faster than before battery pref. showing message : "the battery's capacity is significantly reduced. To restore capacity, please check your service options" Apple support team recommends to change the battery and go back to Catalina as Big Sur not mature enough..., but not sure it will solv my issues ( By the way as I didn't make any back up, going back to Catalina should make me lose the last 3 three weeks of work...)

MacBook Pro (Retina, 13-inch, Early 2015) 250GB available of 1TB . as per previous post installed Big Sur 4 days ago and since then overheating and fan running more often a process named Kernelmanagerd using CPU between 60 to 70% battery draining faster than before battery pref. showing message : "the battery's capacity is significantly reduced. To restore capacity, please check your service options" Solutions found Managed to remove the process named Kernelmanagerd by removing Malwarebytes. Now CPU is less loaded, and the fan also. Battery drainage is partially solved, but I still have the message asking for a change of the battery that has now a full charge capacity of 4823mA only. Seems that Big Sur has a bad impact on the battery... It reminds me what Apple did with iPhones, when they introduced new iOS that reduced battery lifes...