404 errors/new security logs format

Hi there

I’ve been consistently getting a lot of 404 errors and I’m sometimes struggling to work out what’s an error and what’s a bot. I watched this video but I don’t understand:
– how am i supposed to remove 404 errors for images that were in the theme but I’m not using on my site
– how can I stop getting 404 errors for non existent pages that I’m not linking to in my site?
– my logging in seems to cause 404 errors
– examples of 404 errors include -wpe-cdncheck-, /edge-case-nested-and-mixed-lists/, /wp-content/plugins/gxp/idx.php and

Also, the latest version of the logs doesn’t seem to include the referrer so it’s even more difficult to work out! Does anyone have any advice or can redirect me to some more up to date guidance?

Sorry for the long post but I’ve been trying to understand this for a while but not getting anywhere!

Many thanks