I had a Chevy dealer put in a 22 Order for a suburban in August of 21, then I changed my mind and wanted to go Denali. The order got built and arrived at his place around mid October. He sold it same day. I committed to my GMC Dealer to order the Denali on 11/6/21, the order went in on 12/4/21. It arrived at my dealer on 2/6/22, and the only thing missing was Steering Column Lock and 4 way lumbar, all the other options in the current Denali Reserve package were included...at the time of order, Reserve package didn't exist, so I ordered Denali Premium Package, Max Trailering, Premium Capability Package -- which is basically the Reserve Package content now.
My Suggestion is that if you are not in a hurry, and are willing to wait for what you want, communicate w/ your dealer your wants, get a commitment, and then just get the order on the books and let it happen. If you are not willing to compromise, and have a solid vehicle you can continue to drive, just put it in, and let the dealer inventory manager handle it...and eventually they will get an allocation and will order it, then it will get built, and you will have what you want.
I had my expectations set on it getting to me in May of 22, so when it happened in 3 months, I was happily surpirsed.