This is a scary thread. If the new 5.7 is so delicate I'm not sure it is worth it. My old military surplus '77 with a 318, full time 4wd and Dana 60's front and rear was indestructible. You could use gear oil with a little pond water in the crank case and be good until the next change.
There are some nice things about older model vehicles.
My 1985 Toyota Corolla SR 5 was pretty bullet proof and very easy to work on (rear wheel drive), 5 speed and I think 75 horse power. Didn't need the dealer at all and the service manual was easy to read and understand. My wife's 2017 Civic is 6 speed, 175 HP, dual turbo (front wheel drive) and got 47 mpg on high octane no ethanol on one trip.
My 2001 Dodge Ram 1500, 230 HP (rated 16 mpg hwy), 2019 Ram 1500 395 HP and have gotten 22 mpg on a few hwy trips (just maintained the speed limit, no traffic).
It is nice to know your vehicle and be able to diagnose and fix.
My 2019 would not come out of first gear at one point, it was do to a 2 year old battery.
Complexity is the price we pay for better performance and mpg.
I gave my 1985 Toyota Corolla last fall to a mechanic who wanted to restore and older Japanese car. It had sat in my backyard since 2006 (long story, not started in many many years). He started the motor up, no problem from what I was told.