Im sorry if it sounds like a stupid question, but when the pre orders for legends za initially came out, I had no intention to buy a switch 2, but now, I am buying one. I just wanted to know if a switch 1 version would even be compatible with switch 2 because I looked on the Pokemon center website and saw the pre orders for both the switch 1 and switch 2 versions of za were completely sold out, so I have no choice but to have the one for the original switch. I would really appreciate any advice or information about game card compatability.
Yes. While the game hasn't been released, most Switch 1 games are compatible with the Switch 2, and it is unlikely that there will be compatibility issues.
You can also purchase an upgrade pack later as the comments mentioned Source