The 6.2 will blow it away off the line but the 3.0 will tow without breaking a sweat. The 6.2 just eats fuel while the 3.0 sips it, the 3.0 definitely is not a rocket off the line but it has plenty of go to pass.
Our 6.2 eats almost 2 quarts of oil if we go the recommended time between oil changes, GM says it’s within spec, the 3.0 level never changes. Neither have had any issues, our yukon is a 2022 with 49k on it now and my Sierra is a 2021 with 70k on it, both bought new.
We seem to fill up the Yukon once a week and the Sierra every other on avg, my wife drives around 300 miles a week and I drive 250 miles a week on avg.
Def is cheap and if not towing I fill it probably every 6000 miles for around $18. Fuel filters are cheap and easy to replace, I do this every 25k for around $25.
Oil changes, transmission oil drop and filter replace, front/rear differential and transfer case all cost the same in maintenance.
The diesels have an 8yr 80k emmsions warranty and 5yr 100k power train while the gas only has a 5yr 60k power train. Both had 3yr 36k everything warranties.
Penciling it out, the 3.0 has been cheaper to own and held its value better, our Yukon is the Denali and it has tanked in value.
The 3.0 gets to operating temps quick, it seems fine for city driving.