installing Windows while keeping all your files and apps intact

I have been facing an issue in Windows OS that my major apps are crashing, and windows is not all responding normally. I an in insider preview build of Windows and this has been happening since yesterday after I installed the latest Insider Preview Build. Now when I decided to go back to previous version I was  not able to and decided to install normal windows 11 ( public release ) and disengage from insider program but after installing the ISO file and running with all apps and files to be intact after a while the blue screen came to install windows , after which it logged me back to my home screen stating that their was some error installing windows 11 
So if any of the moderators could help me with this ASAP