"One of my client had salary income from a foreign employer, and some self-empoyed foreign income in 2022."

From foreign employer?  Where was your client's employment base and where were services performed?

Self-employed foreign income?  How was the business structure (E.g. sole proprietorship, corporation, partnership)?  Where was the business located?  What was the nature of the business?  Where were the clients based?  Where were the services performed?

It's unusual for someone who has a foreign employer and foreign self-employed income to not take steps to ensure all the conditions for §911 could be met and FTC limitation would be maximized.  Just a bit curious.