After you file

I am more or less in same boat, where I filed the taxes for 2018, 2019, 2020 as single because

initially applying for the wife ITIN in 2019, with 2018 returns, was not received very well by IRS. They asked for her original passport to be mailed and lost it in the process. Somehow we were able to recover if after long fight of 6 months but the end result was the ITIN was not issued bcoz, we needed the passport desperately and IRS asked for additional time to verify the things. We chose for document to be with us over the ITIN being issued!

Fast forward in 2022 and till date couldnt apply for the ITIN, due to some personal reasons and pandemic!!
Reading above comments was very helpful!!
1) Shall I choose for filing 2021 IT return with wife ITIN (W7) application and wait for ITIN to be physically  issued and then, file for amendment of last 3 years (2018, 2019, 2020)!
or is there something else that is suggested!
2) Assuming the ITIN might take beyond April 15, to arrive, would I still be able to amend it for last 3 years!