I am wondering if this "rubber" might be an aspect of coffee, just as the "animal pee" I've read many people complain about is.
Let me explain: Back in the day when I was a teenaged rather new coffee drinker, I fell in love with very dark french-type roasts (rare where I live, especially at that time). This coincided with the first small gourmet roasteries starting up here, and I got a bit crazy and bought a cheap coffee grinder and a french press, kept my beans in the fridge - all that coffee-snob sillyness.
The thing is, how a freshly ultra-dark roasted coffee bean smells is very different from what most people consider "yumm! coffee!". Depending on the type of bean it can also vary quite a bit - the "cat pee"/"horse pee" smell is usually what people notice the most*, but various shades of rubber are not impossible at all - especially after grinding the beans and exposing them to air for a few hours.
Coffee has some extremely complex flavours, and tweaking it in a vape might be difficult, but I think it is probably quite doable. IF you can shake the unpleasant pee/rubber/chemical associations, and in some way integrate those scent/flavour nuances into your idea of "coffee", you can then try to add other things to beef up the nuances of coffee that you like, those that say "coffee!" to you.
(Chocolate and sweet are IMO the first ones to try. Orange or acidic might be useful too. I have absolutely no experience with the various custards, vanillas and creams that are so popular here, but just thinking about how I like my coffee (lots of skim milk, hot if I feel energetic, vanilla ice-cream and cream in after dinner brews if I feel really luxurious), this might be an avenue worth exploring.
If you get the rubber or the cat pee as undesirables in a coffee you probably should not think about tobacco or licorice or anything herb-y, but I could imagine that if your coffee was lacking in those departments (the nuances that when in excess are often described as rubber or cat pee) tobacco or something herb-y or spice-y or even a hint of licorice might be the solution.)
*During this period the parents of a friend of mine had got a present of a bag of coffee that looked very fancy and artesanal. They got so disgusted by the "cat pee" smell when they opened the bag that they immediately threw it out on the balcony in a plastic bag! Luckily my friend knew about my coffee-interest and rescued the bag and asked if I wanted it. I said "sure!", but was a bit hesitant, because the description was so horrible. When I got the bag, it turned out to be a whole pound of my absolute favourite too-expensive-for-everyday ultra-dark french roast that I had been buying 50 grams and 100 grams of as a treat!
