"made in 2021 for 2019"

You are stating this was done Recently = 2021 is not even 4 months old, as of today.

How did they make it? How did they mark it that makes it "for 2019?" The receiving entity doesn't necessarily control or document this. Who made it, how, and how did they mark it so that you have proof it is "2019?"

While you can put into a Roth after the tax return is filed for that year, that still is subject to the contribution window, which for 2019 would have ended on July 15, 2020.