Fail to upgrade to Ventura

Q - " trying to upgrade from Big Sur 11.2 "

A - Trying to upGrade with a computer with an out dated version of Big Sur is not suggested

A- The user would be better served by updating Big Sur to the current version 11.7.3.

A - Then and only then attempt the UpGrade to Ventura

Links below

Keep your Mac up to date - Apple Support (CA)

About the security content of macOS Big Sur 11.7.3 - Apple Support

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this➡️ How to get old versions of macOS ⬅️ and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence.

Make Time Machine Backup  is very useful  Before proceeding