If my index.php file is generating too many processes, can I find out what it is

I noticed something from my website is causing lots of requests and high CPU.

It’s likely that it’s a plugin…

However, I noticed that the index.php file is causing it, but I was told that basically everything goes through that file. In other words, it’s not something within the file that needs to be corrected.

Is there a way to actually tell what is causing the issue, besides the classic turn off all plug-ins and turn them back on technique?

Thank you!