There’s four 404 error messages on my site that I want to delete.

I cannot delete these four error messages I do not understand why.

When I look for the images in my gallery they do not appear, when I look for it on the pages section it does not appear either.

These 4 pages are hiding somewhere on my website, and I don’t know where.

In total it takes a 30 extra seconds for my site to load because of the error messages

The actions I have taken to delete the 404 error messages.

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1. I blocked request URL on chrome dev tools, and did a gtmetrix report, and it looks like the performance is still the same.
2. I submitted the pages to google search console so they can delete it, I’m not sure if they’re going to do that because it was actually my first time submitting a page to search console for removal, so its still a bit unclear for me, and google is still in process of removal, and I don’t know how long that is going to take.

i'm pretty sure i'm looking for the messages in the wrong place.

Can someone please tell me what actions I need to take to remove these error messages from my site?