I wrote reoprts to Zendesk about those issues, here below are their answers:
"We are aware of performance issues for some users on XBox Series S/X that have started occurring since the release of SU13.
There is a new beta testing for Series S/X users that will help the development team gather data to troubleshoot the root cause of the issues. See the link below if you would like to assist them in gathering the data:
We are aware of this issue since the SU13 full release. There were changes made to how the sim prioritizes data on the XBox (to limit the avionics black out issues) which have now caused the unintended side effect of more crashes for some users since the full SU13 release. I know this can be frustrating for you, so we do apologize for the problems that you have been experieincing. Just know that this is currently the number one focus of the development team currently.
If you are already enrolled in the beta testing, then there is nothing more that you need to do. In fact this means that all the crashes that you have been experiencing have already been reported back to the development team which is good data for them to work with".
If you have Xbox Insider App you could head to Rewiews - Select Microsoft Flight Simulator stability track test - Click Save - Wait for enrollment to finish - Restart Xbox and the beta track stability test update will be prompted.
(For Xbox Series X users)