Look, this is directed at the ones who strap on their helmet, tighten their bootstraps, and get dirty in the system application Settings trying to squeeze battery life by setting App Battery Usage to Balanced or Restricted. U know who you are, no need to feel ashamed. What you should feel is downright silly thinking you knew better than the Programmers...tsk tsk.
After I reset all my system apps back to Unrestricted everything is snappy as it use to be!
To achieve this go to Settings > Apps > Top right 3-dot > enable system apps
Then select every system service and app and reset back to Unrestricted.
Further testing is needed but this may also be required if you ever reset app preferences