If you’re getting a 5ver then yiunofetty much need a HD pickup. Gas or diesel depends on how big and your preference.
In your current sitch, 35k miles a year, you’re paying about $2500 a year more in gas than diesel compared to a 1/2 ton diesel pickup assuming $3 a gal for both.
That depends on your locale and fuel prices.
It rarely makes sense to have a commuter car (which is all you “need” for 30k of those miles), but in your case it may make sense financially given your scenario.
On the flip side it appears you are not a mechanic (ie no driving clunkers to save a buck) and financially stable enough to afford piling up the miles on a $60k gas guzzler.
Depends if you’re running the numbers for economy or planning for your next “luxury.”
Big gasser trucks will get 10-20% less mileage than your Tahoe and big diesels will get 10-20% better mileage, gas tuck cheaper than a new Tahoe. Diesel truck about the same cost.
I say life’s too short to drive something that doesn’t make you look good (if you can afford it), so buy what makes you happy. You can make the numbers work compared to the Tahoe with pretty much any of the options you’re considering.