IMO it comes down to preference and nothing to do with the gas prices. I love and prefer the range and power delivery of diesel compared to gas. Came to Gm from Ford due to GM offering multiple diesels throughout the lineup. Started with purchasing a 2016 Canyon 2.8L LWN diesel for my daughter's first ride. Absolutely love that little thing and have towed cattle and our deckover trailer with it often. Next we picked up a 2018 GMC Terrain with the LH7 1.6 diesel. Thing has been one of the most fun little commuter/beaters I've ever owned. Long trips with little luggage and daily driving is an absolute blast and the handling on it is equivalent to many sports crossover and SUV's that I've driven. As the daughter graduated from HS and now is in Ag/Large Animal Science at CSU she needed a larger truck capable of hauling larger loads and I ordered her a 2021 AT 1500 with the LM2. While waiting for it to come in, a dealership in Denver had one hit their lot when I was visiting and we swung over to get a test drive. I was so blown away that I ordered one for myself in the Elevation trim.
Since then my wife has fallen so in love with my truck that we sold her POS Expedition Platinum and until I can find her a 2021 Denali with the LM2 3.0 diesel I'm stuck back in the Terrain.
Is it 6.2L power absolutely not. I'd compare it to a 1st Gen Turbo Diesel tuned. As soon as tunes are available for these LM2 powered rigs they absolutely will however blow 6.2L away. They are extremely detuned for emissions. We have since towed all over the western US with them with zero issues. For daily commutes they are a blast to drive and there is zero need to WOT them like a 5.3L while towing or to merge. I've also driven the Ford and RAM variants and would say those are more Euro spec high rev diesel's while the power of the LM2 is more of the American diesel power delivery I'm used to from my HD diesels in my fleets and driveway.
So look at the option as more of a top option purchase than a comparison to the 5.3L savings. It will absolutely hold a higher value down the road in the thousands of dollars just like my Excursions have. You can get a 5.4L Excursion all day long for dirt cheap, while the 7.3L Excursions are bringing premiums close to or above original sticker price.