You mean the feat that gave you luck, skill, divine, etc. hit points? Yeah, you were tougher, but tougher =/= more con. And yes, you can learn to be tougher. That's what skill is.
Oh! So Constitution is luck then. Guess that answers the question about halflings you asked earlier. Because, you do realize that tough is +2 hp per level, and if you raise your constitution then you get +1 hp per level, it is literally one of the only things con does other than constitution saves. So, if more hp = more luck then constitution is the luck attribute.
You can argue that hp is divine providence or skill or luck or anything else, of course, but "tough" doesn't mean those things. The general understanding of that feat is that you get physically tougher.
Or a strength penalty. It's not a racial ABILITY. It's simply a cultural norm for the race to learn it.
More culturally learned skills?
Huh. This is a weird argument for you to make Max. Because you've just undercut your own objections.
If the "racial abilities" of elves can be culturally learned skills that aren't tied to a stat, and feats are learned skills that don't need to be tied to a stat... then why can't elves have racially "cultural feats" tied to dexterity? Even if they have no dex bonus you have already established that
a) feats are learned
b) it is perfectly acceptable to have learned abilities that have no ASI attached to them.
So... there is no problem.
False Equivalences are false. Stonecunning does not make the dwarves come across as wiser, smarter, or more enduring. An ability that makes elves more dexterous than other races would.
Here's a valid example of what I'm talking about. If dwarves were given the ability to endure a lot more than other races, which implies a much greater con, but yet had no con bonus.
Or else not. None of your examples is in any way a counter example to what I have been saying. Not one.
But, that's exactly what Tough is, a learned skill that allows them to endure a lot more punishment. So, since that is a learned skill that is in no way tied to a racial ASI, then we can give dwarves a culturally learned skill (feat) that allows them to be tougher with no racial ASI for con, and it isn't nonsensical.
Done and done.
Nobody said otherwise. My PC knows that elves are more graceful(dexterous) as a race than humans, though. That's a fact.
No, if your PC said that was a fact, they would be wrong. They may know that on average the average elf tend to be slightly more graceful than the average human, but that's about it.
Which then gets into some weirdness and some near eugenics level stuff, if you caring about that +2 Dex is because of roleplaying that your character cares about the fact that statistic. Which, to remind you, is what you said right here.
My PCs care about their races and belong to them, and since I'm the roleplaying that, I care about those things as well.
With regard to racial ASIs your PCs know about them and care about them, and therefore you do as well.
But, it doesn't matter, because we solved your "it's nonsensical" problem already.