Need to file amended return for 2020

I am a US citizen living abroad (so tax deadline is June 15). I filed on June 10th and received an email that the return has been accepted. Today I realized that I forgot to prepare form 8949 for our crypto transactions. Should I file the amended return right away or wait until I have received my refund? The crypto transactions will reduce the size of my refund, but it will still be a refund situation.