Unfortunately there's a disconnect between how things should work and how things actually work.  I'd strongly recommend the client just pay the $2K and get the money back when filing the 2022 return.  The overpayment applied is purely a timing difference.  Pay that money now, get it back later.  The fees I'd charge to argue with the IRS about where the money should have been applied are a permanent difference.  Pay me now for my time, I'm not giving it back later.  "I'm happy to go either direction, Client let me know how you want to proceed." 🙂

That said, you should be in the time window when the credit elect can be reversed.  See IRM 21.4.1.5.6.1(3):

https://www.irs.gov/irm/part21/irm_21-004-001r#idm140355427501440

We're still in the window for this to count as a superseding return.  But IMO you're swimming upstream for a measly $2K.  I wouldn't expect the IRS computers to handle this properly but if you could find a human to open the mail or answer the phone it should be fairly easy.  But then that's not the world we live in at present.  YMMV.

Rick