If the OP is looking at midsize front wheel drive unibody suvs, so not sure where a 3/4 ton Ram comes in to that picture, but?
OP, you answered your own question pretty much. You got about 200k out of the engine and over 300 out of the transmission and axles it appears.
“Most” other common components, front end parts, engine accessories, brake systems are going to last for 150-200k miles.
“Reliable” is relative. A $20/20minute to replace part can leave you sitting on the side of the road just as easily as a $2500/20 hour part.
Personally I wouldn’t have spent any real money on the old truck after it had so many miles. Gotta know when to hold em and when to fold em.
Regardless of this or any advice, just get the lowest miles best condition you are ok with paying for. Can’t do any better than that and you’re admittedly not the folks to be gambling on high miles.