You may have already solved the issue. If not I suggest these from Amazon.
https://www.amazon.com/gp/product/B01GQPZYNK/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1. They are AC Delco air shocks but non magnetic at 1/4 th or less the cost of the mag versions.
I just installed these on my 2016 Yukon Denali with the Z95 magma ride / air shocks. I wanted to keep the air ride height for towing but ditch the stiff, high failure rate and OMG expensive magnetic POS shocks. I made my own mag shock bypass resistors. But did not bypass the ride height sensors to keep the auto level active. The ride difference is night and day. Smooth ride on my 3 miles of rough dirt road to my homestead. Good handling on the curvy mountain roads around here too and stable at freeway speeds. I also ditched the 22 inch super sports car wheels with 17 inch wheels with 265 70 R17 tires. You will not be disappointed. The biggest challenge was trying to get a 21 mm socket on the inside top shock bolts for removal. After several experiments with various length 3/8 extensions, deep well 6 point 21 mm socket and holding my tongue just right I finally got those stubborn top bolts removed. The resistor bypass I made with two 3 ohm 100 watt resistors in parallel to get 1.5 ohms and I found the OEM mating connectors so as not to cut and splice any wires. I have pictures of everything if interested.
Editorial side note … It did not take long to figure out there many businesses out there making a living undoing what GM has done to suspension. In theory it works but in reality the OEM ride is theoretically smooth for the first 50k miles more or less.
I just realized this is a March 2020 post not a 2021 sorry my bad but I’m not deleting all this stuff I wrote.