I'm trying to use the YRSUSA2 variable but it says it's not included in any ACS dataset, which can't be correct.

Any query using yrsusa2 doesn’t run.

Do you have suggestions as to what’s wrong?

It sounds like you are using SDA. I just tried looking up YRSUSA2 in several ACS samples within SDA, and everything seems to work well for me. Perhaps try restarting or using a different web browser and try again. Let us know if this doesn’t work.