At 8000 pounds trailer weight I would stick with a 3/4 ton gas engine. The emissions systems on diesels have made them way to unreliable. It is also about a $10,000 cost premium to buy the diesel plus the added maintenance cost.
As others have said watch the payload rating. Many 1/2 ton trucks are advertised as having 12-13 thousand pound trailering capacity. With a payload typically between 1200 and 1500 pounds for a 1/2 ton you can really eat into that with a tongue weight of up to or over 1000 pounds.
I am using a 2024 Chevy Silverado 2500 with a 6.6 gas engine to tow our 7000 pound trailer. Today is only the second time I have towed with it but initial impressions are really good. Plenty of power, and a comfortable ride. Downsides would be fuel mileage looks like it is going to be around 10 mpg towing. It is also a big truck when you are in a parking lot. Not the ideal daily driver but a real beast of a tow vehicle. Previous tow vehicle was a 1 ton Chevy van.
Ford vs Chevy vs Ram, yep just like Sram vs Shimano vs Campy. Ford 7.3 had initial great reviews but are getting reports of camshaft failures. Ram has cylinder deactivation on their gas hemi which has also caused cam and lifter failures. Chevy 6.6 gas had reports of early engines burning excessive amounts of oil. Each can have their issues. I only have a little over 2000 miles on my truck but so far it hasn't used a drop of oil and I have had no complaints.
