Should I amend or not?

I efiled my 2020 return on May 3, 2021 with a Federal refund amount of $4600. Unfortunately, I still have not received the refund and the IRS website just says my return is being "processed".

 

I got frustrated and called the IRS and I was finally able to reach a live agent yesterday. She stated my return has not been processed and said I need to wait. She couldn't give me a good reason why it hasn't been processed yet.

 

So I pulled my tax transcript (hoping to see a clue on why the delay) and found something that might be the reason for the delay. I had a gambling winnings of $1200 from many months ago that I forgot to report. I'm guessing the hold up is due to my efile information not matching what the IRS has due to this omission.

 

So the question is, should I file an amendment now? Is it OK to file an amendment knowing my return hasn't been processed yet? Or should I wait for a response from the IRS (only god knows how long that will take) and go from there?