Retirement tax questions

I'm in a similar boat. I've over contributed to my 401k across two employers in 2021. Unfortunately, I just realized this now and there isn't enough time to get the excess contributions returned by April 15th. Should I be filing my taxes as you mentioned by including the excess contributions as income in the "Less Common Income" or do something else? 

 

Secondly, can you confirm or correct what I should do next: I should still contact my employer and retirement plan provider to correct the problem so they can return the money and send me a 1099-R for next year. I understand that I'll be taxed again on the excess contribution + any gains. Is that right? 

 

Btw, your advice and answers are very thorough. Thank you so much for helping the community!