Chrome using 20% CPU

Upgrade your processor and get speedier ram.

Maybe some extensions are the reason why you have 20% CPU usage.

Use microsoft Edge. It uses way less ram and cpu than chrome. Just change default search engine to google, you never notice that you were not using chrome.

Facebook is a malware, also is chrome. I use brave browser (chromium fork) and it works ok in most sites, no problem. But it blocks javascript.
The "problem" however might not be a malware but the language of the sites like bootstrap or react.js that excecute a portion of the code in your computer to do whatever facebook is doing like spying on you, maybe.