I've seen a few of these type of cars.
The items that can't be installed/optioned without the 1LE package are the eLSD rear diff, 285/305 staggered forged wheels, MRC calibration, and suede shift knob/steering wheel. You could add the wheels and suede yourself, the MRC calibration and eLSD cannot be done though.
The highest overall optioned 2SS from 2019+ was this one with $24,130 in options. Considering the lowest priced ZL1's were $65,585 MSRP for that same year, someone really wanted that spec lol
Some others I posted here
https://www.camaro6.com/forums/showthread.php?t=634877