Apple 2013 mid Mac air cannot be updated to Big Sur where the software is supports according to apple guidelines

I recently got a old mid 2013 mac book air from some one else and reset to the factory settings and installed the operating system again it is OSX where I checked the eligible os which is big sir where I can't update directly because they ask minimum version to be 9.0 or higher which in my case 8.5. So I tried download the manual way and got the file and tried to run to install the 10. Version where it shows unsupported format. The hard disk is 160 and it's fully erased but space or the cache is not the problem since this looks a fresh. I watched many videos and read articles to find the issue but it didn't work until now. Also I had some updates which I did but there is a one error I got which is 102 error I googled and try to sort they easily ask me to restart or off the lap and on again which I did nothing worked.