See some articles If kernel_task is using a large percentage of your Mac CPU - Apple Support
See how apps affect Mac performance, battery runtime, temperature, and fan activity - Apple Support
To quit a process, first try quitting it normally. For example, quit Safari by switching to Safari and choosing Safari > Quit Safari.
If you can't quit a process normally, you can use Activity Monitor to force it to quit. Save any documents related to the process, then select the process in Activity Monitor and choose View > Quit Process.
If you don't recognize the name of a process, it might belong to macOS or another process that you do recognize. To see the relationships between processes, choose View > All Processes, Hierarchically. If you see that a process belongs to an app, such as Safari or Mail, quit the app before deciding whether to quit any of its processes.
To help avoid malfunctioning processes, keep your apps, plug-ins, and operating system up to date.
In normal working Mac , network incoming and outgoing packets must be zero and there are no collisions but they are varying in your Mac as shown in your screen shot .In recent networks there must not be any packet loss .
Do you use air port router ( hard reset it ) , and what are the settings for service provider router ( hard reset the router and check the box of firewall , and set as automatically ) and what apps have been installed in the system .