With a new item highlighted in the Item field, I tried pasting the following in a grid:

You may use a capturing group in your regex to make REGEXEXTRACT return just that captured part:
=REGEXEXTRACT(D1;"end\s*(\w+)")
If you need to return 1, 2 or 3 whitespace-separated words after end, use
=REGEXEXTRACT(D1;"end\s*(\w+(?:\s+\w+){0,2})")
See the online demo (Golang regex also uses RE2).

From Paste Options I selected to create 5 new items for the 5 lines in the text.  The lines beginning with =REGEXEXTRACT didn't get pasted.  The items were created for those lines, but the Item field is empty in those two lines.

I guess IQ sees those two lines as equations?  And because the "equation' is meaningless to IQ, the evaluation fails and nothing gets pasted?

p.s. after entering search terms in the website/forum search box, an error message appears in a red shaded box, with the following message:

"Warning: count(): Parameter must be an array or an object that implements Countable in _filter_url() (line 536 of core/modules/filter/filter.module)."