The latest upgrade to Adobe Photoshop Lightroom 5.7.1 is Adobe Photoshop Lightroom Classic is version 12.1.
So yes Lr 5.7.1 is redundant and can be uninstalled if you wish.
A Lightroom 5.7.1 Catalog file can be upgraded to function in Lightroom Classic 12.1 but not the other way. i.e. Lightroom 5.7.1 cannot read a LrC Catalog.
Lightroom Classic is 7 upgrade versions ahead of Lightroom 5.7.1 with far more advanced features.
Regards, Denis: iMac mid-2015, 5K 27”, GPU 2GB, Ram 24GB, HDD 3TB, macOS 11.7.6 BigSur,; LrC 12.3, Lr 6.3.1 Ps 24.4.1,; ACR 15.3,; Camera OM-D E-M1