How do I see all the feedback entries submitted by myself?

When you get there, you get all the feedback that were created with the same account.

I see the FB dating back to 2015.

I see feedback from others, too.

That sounds like a serious bug! (Have you filed a bug report? Ha ha ha)

But maybe you're just referring to the spam that Apple puts in there, e.g. release notes, newsletters, surveys etc. I'm afraid you just have to ignore that.

Or... maybe this is an enterprise thing? Are you seeing bugs from other people in your organisation? I don't know how that is supposed to work.

in the Feedback Assistant app, there's a filter.

In my macOS browser, the filter does not show the same options as yours