The CPU can be upgraded only be replacing the entire system board -- and while there are faster options, the cost and age of the system point toward a better path forward:  a new(er) system.  This one is a dead end as far as Windows 11 is concerned, and it's on the order of 6-7 years old, as will be any replacement boards you can source.  
my device work in intel i3 6006u cpu [NAME].00 GHz 2000Mhz 2 core 4 logical  but very slow wroking can i upgrade my pc processor
inspiron 15 5567 upgrade processor