Thank you for this!
I contacted a tax lawyer and they emailed me with the below:
After our call, I did some research with regards the IRS legislation surrounding the Green Card and in particular if you can delay filing a return until you have actually arrived in the US. The good news is that, assuming you do not go to live in the US until 2023, you will not need to file a 2022 US Federal tax return, even though you are now a Green Card holder. Generally, a Green Card holder is treated in the same manner as a US citizen however, where you obtain a Green Card in one year but do not travel to the US until the following year, there is no need to file a US tax return in that first year. Please see the link from the IRS code:-
https://www.irs.gov/individuals/international-taxpayers/residency-starting-and-ending-dates
This means that the first year you will need to file will be 2023 and the deadline for filing is not until April 2024.
This confuses me slightly because they told me I did not have to file a return.