how to export 2021 transactions from my Apple cedit card?

MY bad - I didn't follow the instructions 100%.

pressing your "Card Balance" number on your smartphone

That was the clue. What I had tried originally from the MAIN page in the wallet was scrolling down to 2022 and tapping on my September transactions. Despite the explicit instructions, it wasn't 'visually' intuitive to me that tapping on Card Balance would DO anything.

Thanks for the confirmation that it DOES still actually work and for the clue I'd missed.

There is no option to export an annual statement.

You can export individual months by logging into https://card.apple.com/ and click Statements in the sidebar or you can use an iPhone as described in Download or export your Apple Card statements and transactions - Apple Support

I just followed the instructions in Download or export your Apple Card statements and transactions - Apple Support and it was exactly as described in that support article.

At what point in the instructions does it go wrong for you?

Not true. I thought I'd done this before, but I see no option in the Wallet to export transactions as described in the article you referenced above. Can I buy a vowel :)