Similar issue with my 2020 Denali. Oil consumption test from dealer indicated almost 2 quart consumption in 1700 or so miles. Was around 16,000 miles on truck. Dealer Tore down motor, ash on one piston and cylinder walls scored. Motor replaced and then ran into a few electrical gremlins.
3 different trips to dealer to deal with electrical stuff. Appeared to be some chafing on wiring harness either from engine swap or another TSB - sorry don’t have number. Now have about 1000 miles on since last issue. Hoping all resolved now.
Good luck driver eye. Keep us informe