Not complete BC though but I guess you are aware of that?
XSX has BC with:
Still better than PS5 BC but far from complete.
Unlike Sony however, MS is showing initiative to move forward with BC. Overtime the available library will become closer to complete than a lot of people think.
With the PS5 however, what you see is what you get outside of potential streaming qith PSNow. And that is a far cry from being able to run the games natively on the console, or use your old disc to claim ownership.