You'd be better off buying one in Texas and having it shipped to your location. I also live in Southern California and had been looking for a year for my Yukon AT4. Bottom line, I too kept hitting that markup "roadblock", so I expanded my search for 2000+ miles. For the most part, a lot of the vehicles that had the options I wanted were already spoken for before it hit the lot, but I was lucky enough to find a rural Mississippi dealership that just got a Redwood Metallic earlier that week. It didn't have 3 of my options, but it did have the must-have ones... So I bought it and had it shipped here to Los Angeles. AND, that process was a lot cheaper than paying $10k over sticker. I still paid $3k over sticker, but that plus shipping, and I still saved $5000 over what I would have paid here in California. That was just two months ago when I had mine imported from Mississippi.
As for Texas, Denali's and AT4's were harder to come by because most of Texas won't charge a dealer mark-up, and those are the most desirable trim levels. I came close a couple of times, and even tried offering $15k over sticker for a few fully optioned AT4's, but they were loyal to the customers that pre-ordered them and wouldn't budge.
If you want to talk California registration and emissions, you don't have much to worry it passing since most new vehicles have 50 state compliant parts. It was a two week-long process that involved putting 500 "illegal" miles on it because the oxygen sensor was so new that it was giving off toxic readings. I say "illegal" because I drove it without being registered while putting on those 500 miles, so I could have had it impounded if a cop having a bad day pulled me over. Putting on the added miles to pass my smog was the idea of my local smogger, because he had a 2022 Corvette have the same issue a month prior, and I only had 13 miles on mine when I got it. After I put on the miles, it passed with no problem. Then came the DMV visual inspection, California sales tax, and just like that, I got my license plate that same day I registered it. That was back in late March this year.
Good luck in your search.