Hi Shreyas,
I am Sumit, an Independent Advisor here to assist you.
9900K is supported. The Secure boot is a problem.
Please look for Secure boot option in the boot tab of BIOS Settings. If you are not sure, send us a screen using your phone's camera.
https://smallbusiness.chron.com/bios-msi-mother...
Standard 3rd party link disclaimer:
There may be links to non-Microsoft websites that would provide accurate and safe information. Watch out for ads on the websites which are frequently classified as a PUP (Potentially Unwanted Products). There is no need to buy paid products to fix your computers as they do more harm than good sometimes.