I think you are correct to look at the non-turbo diesels for more longevity. I suspect those were the "1M mile engines". The turbo can quickly ruin an engine from overheating the aluminum pistons, as true for gas engines too. The OM617 turbo has special pistons with oil-squirters underneath, but if boost is set too high, even that won't suffice (be careful messing w/ boost setting and ALDA). The turbo version also has a chain-driven oil pump which adds complexity (plastic guide rail fails). My 1985 CA turbo engine failed at 330K miles (chunks missing from pistons). Prior owner was a lady who had it religiously serviced at M-B dealer (thick folder w/ high bills) and I always drove it carefully.

I think all 1986+ diesel engines had aluminum heads and/or blocks, which can be damaged by a single overheat. The 1986+ 6 cyl diesel is much more powerful, but seems less reliable. The ~2004 CDI common-rail diesel engines are much more powerful and efficient, but much more complex. A 1970-80's non-turbo engine is much easier to work on, as you can much more easily swing a wrench in the engine bay. If you do need to rebuild the engine, new pistons are affordable (though not like a small-block Chevy V-8) vs the >$500 each turbo pistons if you can even find a set. Accelerating fast is over-rated. Most people just want to get to work dependably. If you live in L.A., a Lambo is a waste as you will rarely see average commute speeds above 10 mph on I-5 and I-405.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans