Revoking the FEIE

Up through 2017, I used the Foreign Earned Income Exclusion when filing my taxes.

In 2018, my foreign income was under the standard deduction amount, so I didn't bother to file the FEIE. I didn't realize this amounted to revoking the exclusion, which I did not formally do.

In 2019 I had no foreign income.

In 2020, I used the Foreign Earned Income Exclusion, which I now realize I possibly did erroneously.

I also now realize that I should probably be using form 1116 since that will allow me to claim the alternative child tax credit (which I did in 2017).

I'm wondering what to do now? I'm thinking I should ammend my 2020 taxes using 1116 instead of 2555 to claim the child tax credit. But do I include a formal revocation of the FEIE there? Or do I go back to my 2018 taxes and refile those with a formal revocation (I think I can just about squeak that in as I filed on 15th June 2019)?

Also any risk or anything else to consider in this scenario?

Up through 2017, I used the Foreign Earned Income Exclusion when filing my taxes.

In 2018, my foreign income was under the standard deduction amount, so I didn't bother to file the FEIE. I didn't realize this amounted to revoking the exclusion, which I did not formally do.

In 2019 I had no foreign income.

In 2020, I used the Foreign Earned Income Exclusion, which I now realize I possibly did erroneously.

I also now realize that I should probably be using form 1116 since that will allow me to claim the alternative child tax credit (which I did in 2017).

I'm wondering what to do now? I'm thinking I should ammend my 2020 taxes using 1116 instead of 2555 to claim the child tax credit. But do I include a formal revocation of the FEIE there? Or do I go back to my 2018 taxes and refile those with a formal revocation (I think I can just about squeak that in as I filed on 15th June 2019)?

Also any risk or anything else to consider in this scenario?

You must attach a statement to formally revoke the 2555 exclusion. Simply by not having foreign income and not filing a 2555 does not automatically revoke. You must wait 5 years I think it is before you can use the 2555 again, meaning 1116 only for those years.