com.apple.webkit.webcontent highly load CPU

You can try that, but the problem may not be related to the particular browser you're using. It is related to the content delivered by the websites you load, and the manner in which that browser processes it.

For Safari, review the suggestions in If Safari is slow, stops responding, quits unexpectedly, or has other issues - Apple Support.

Read these articles : Use Activity Monitor on your Mac - Apple Support

: If kernel_task is using a large percentage of your Mac CPU - Apple Support

One of the functions of the kernel task process is to help manage the temperature of your CPU.

Activity Monitor might show that a system process named kernel_task is using a large percentage of your CPU, and during this time you might notice more fan activity.

One of the functions of kernel_task is to help manage CPU temperature by making the CPU less available to processes that are using it intensely. In other words, kernel_task responds to conditions that cause your CPU to become too hot, even if your Mac doesn't feel hot to you. It does not itself cause those conditions. When the CPU temperature decreases, kernel_task automatically reduces its activity.

See how apps affect Mac performance, battery runtime, temperature, and fan activity - Apple Support

Quit any malfunctioning processes

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.

Some web page content will do that to WebKit, even web page content that appears on its face to be simple and innocuous, lacking any obvious complexity. The resulting monopolization of a Mac's CPU can cause the entire Mac to become less responsive or effectively unresponsive, increase its exhaust fan speeds, consume copious amounts of power, make it uncomfortably warm, or all of the above.

WebKit is not exclusive to Safari.

If and when you can isolate a particular web page that drives com.apple.webkit.webcontent to extremes, at your option you can use Safari's Develop menu to examine its content, perhaps find out what's wrong with that page yourself, or refer it to its developer, or to Apple for examination:

Safari for Mac: Use the Safari Develop menu

Yes, for now, until the website's creator is motivated enough to fix their content, or WebKit's code is changed to cope with whatever causes the problem, or both.

Problems such as this are going to exist forever because as long as web browsers exist, their development will never stop. Website content creators are (generally) paid to develop eye-catching and commensurately performance-demanding websites, because those effects tend to impress the (generally) technologically challenged people who employ them. They almost never consider how well those websites work for the people who actually use them – at least until it begins to affect their bottom line. If using Amazon's website (for example) caused people's computers to melt, no one would shop on Amazon.

Poorly implemented websites are generally those with a captive audience. For that reason, government agencies and insurance companies are among the worst offenders, and it's only recently that certain of their sites no longer unreasonably demand Microsoft Internet Explorer. The FAA's website comes to mind.

Apple's Safari isn't the only user of WebKit. There are literally dozens of other browsers that use it, but 99% of them are probably unknown. If any particular browser chokes on any particular webpage, the only practicable workaround for end users is to use a different browser for that webpage.

Maybe you have Flash enabled?

Here an old discussion about a similar issue: Safari Web Content high CPU usage

That problem is caused by one or more websites open in a window or tab Close each one to isolate the cause.