catalina or Big Sur installation

I had to erase everything from me MacBook Pro. I took copy out of all docs and other files of what I wanted but don't have any back up. I tried installing catalina or big sur (I was running big sur earlier) and it seems to be giving me checking Null issue during installation.

Currently I have Sierra and want to upgrade to big sur but if not possible then at least catalina.

can you please assist. many thanks