case sensitive would be how the hard drive on the 2011 is formatted. case sensitive allows files named the same thing with different capitalization or lower case to be different files ; e.x. "BLuePanDa.jpg" is not "BluEPandA.jpg"
there are a few ways to do this, one is backup the drive with time machine and restore the account on the 2020 with your migration assisting using the time machine drive you backed up. another would be copy the drive, reformat the drive, copy it back.
what I've found to be easier in the long run is to install the software you need on the new Mac, this way you have comparable versions then update that software if it's needed then share the 2011's drive out, share your users folder then just copy the files were you need them.
If you share the drive over the network the whole case sensitive thing is ignored when moving the files from the drive to the new one; unless you have files with the same name regardless of upper/lower case. ex.
e.x. "BLuePanDa.jpg" is now the same as "BluEPandA.jpg"