50s, 60s, 70s, 80s 90s Detroit luxury.... in new(er) cars

Hello... and might I please ask for opinions:
I am 73 years old, without a spouse, and still working full time. I drive 1500 miles per year, currently in a 1999LincolnContinental, which looks new. I routinely keep a car for 20years, so my next purchase will need to last for the rest of my life. I fully understand that cars need to be properly maintained, and luckily, I found a very good garage near-by, whose owner is foreign-born, and is thus familiar will all types of car-repairs; going to the Dealer is not how I was trained by my Father.

I'm sure that many readers will intuit what the current dilemma is:

What do I buy, as a late model pre-owned car ( as I cannot possibly justify a brand-new car when driving only 1500 miles per year)... that is reminiscent of the output of "classic" Detroit, when luxury marks were luxurious and posh without apology or explanation; this is the kind of car I grew-up with, as-in: Lincolns and Cadillacs. I really wish to stick-with a classic sedan or coupe rather than a cross-over/SUV type vehicle. My preference would be to buy "American" ... but "the pickins' is slim". If I were to choose, overall, the Mercedes CL-class comes the very closest... but friends have warned my that the maintenance on this type vehicle is is absurdly and unrealistically expensive . Again, I understand the concept of vehicle maintenance... but if annual maintenance approaches $5,000.00, frankly: "I'd rather have it hanging from my ears"!
Please assist... referencing the above as guidance; I shall sincerely thank-you in-advance for your kind efforts.
Belonging to a different world... apparently long-gone,
Sandrine