A pretty interesting cocktail - upon tasting, I couldn't shake that this is a mezcal Last Word/Closing Argument without the citrus, leaning towards the profile of an Old Fashioned-style of drink. I'd fully expect that as a template, you can experiment with just about any amaro out there to substitute the Lucano to create vastly different drinks. I also do agree that 1 dash of any bitters probably helps this cocktail out a lot if a more delicate amaro is chosen.
On a second round, I attempted the recipe with Amaro Nonino to replace the same amount of Lucano, and added a single dash of chocolate bitters as Paul Green below had suggested - quite enjoyable!
Montenegro is a very different animal, and while closer, Averna is different again. To properly experience you'll need to invest in a bottle of Lucano.
Wanted to follow up by saying the drink came out fantastic. Thank you Diffords for the cocktail suggestion! I’ve been looking for a variation of the M&M and I wouldn’t have thought to add Luxardo maraschino liqueur. For anyone interested in Doc Hersons amaro, it’s wonderful: https://www.newyorkcraftspirits.com/products/doc-hersons-bitter-liqueur
Excellent combo, the smokiness plays so complimentary to the amaro, and the hint of cherry rides shotgun so well. I'm tempted to add a dash of cherry bitters or ¼oz cherry liqueur to see what happens but definitely excellent as is.