Dropping $5k on an old oil patch truck with a pile of miles on it is foolish, but to each their own.
myredracer, your observations are expected and totally normal. My 2016 1500 Silverado work truck with a 5.3 and 3.42s and 6 speed pulls as well as the new 6.0/4.10 3/4 tons and better than the 08 and 2012 models we still have hanging around. Just how it is. They're good reliable engines, but under powered by today's standards unfortunately. Even GM's new 6.6 gasser coming out will move them from 3rd place by a large margin to 3rd place by a smaller margin.
The truck will work for you, don't waste your money on a chip, spend $10 on a bottle of Tylenol for the headache instead and $10 on a 6 pack to forget about the slow ride uphill!
On the upside, they are nice comfortable durable trucks and now that you have a good set of wheels to drive, if you don't like it long term, you have a good stop gap while you can hunt for another V10 Ford at your leisure on your own terms. Chevy will sell well and quickly if its in good shape.
My go to for a newer used gasser HD pickup that needs to tow 4 tons in the mountians would 100% be a 2011-2016 F truck 6.2 and 4.30 gears. Best combo of power, comfort and value......and I don't even like fords, lol!