When I found myself in need of a new truck, I went and looked at quite a bit of used 2014 Silverados. All were clean. I knew that since it was going to be my daily driver, I needed the MDS or something similar. My old Ram gave me pretty decent gas mileage for a truck and I was hoping to have the same.
The last I checked, GM has a lot of issues with its cylinder de-activation; even more so than the Rams. MDS was partly developed and borrowed from Mercedes during their ownership of Chrysler, hence why out of all the American engine systems, I consider it the best.
In my comparison of the Silverados, I found visibility to be an issue on the new ones. You sit so low in the cab like you're in a sedan. Doesn't give it a commanding view especially when you venture off road; which is what I was doing. GMs interior trim isn't as good as the Ram; even when I was buying it new back in 2014. Still isn't today. Another thing is that handling of the Ram is better than the Chevys on the road because of the coil rear and sway bars.
I ended up getting another 2014 Ram just like the one I had before and frankly I could be happier. When it came down it, for me, after experiencing the Ram, following the developments of all the trucks closely, I would take a Ram over any of the others, GM, Ford or even Toyota.
You got yourself a good truck. Stop worrying and start enjoying it. If there is something that you don't know or understand, you can ask a question on here and someone will respond; no matter how dumb. I know... I've done it myself a few times.
My recommendation, change all the fluids if you aren't sure of the history, get yourself the service manual and follow it to the letter. Use the right engine oil and when in doubt, just stick with Redline 5W30 (Speaking from experience).
You may not enjoy all the screens and stuff now, but give it time. After a while, you will ask yourself how you ever did without. I felt the same when smartphones came out, until I got one myself.