This is simply not true in any meaningful fashion.
You're stretching ridiculously to find deep-lore enemy NPCs, often from far in history, to justify one of the party members being Iron Man. It doesn't work. I'm unable to even think of who you're referring to re: Dragon Age though.
Rune-carving dwarves is what I'm referring to from Dragon Age. Specifically, Sandal Feddic, who uses Lyrium to carve magical runes into mundane objects that (off screen) allows him to kill a lot of enemies, and he can enchant the main character's armors/weapons
Artifabrians in the Cosmere use tuning forks, specific metals, stormlight, and gems to trap magical creatures (similar to elementals and fey) in devices that can harness their magical energy and produce a variety of effects (which may or may not be connected to the Surges). That's a pretty similar concept to D&D Artificers, which use objects to tap into the Weave and cast "spells" and make magic items.
The same is true for a lot of the D&D settings. I only argued re: Lantan because it's so obviously bollocks. You described what Lantan artificers actually do. What they don't do is run around with magical gun-turrets or dress up as Iron Man in super-duper magic armour.
And the Battle smith pet pretty much always requires reflavouring as well, to not a bloody robot to fit into most settings without changing the tone of the setting.
Nimblewrights and guns come from Lantan. A Lantan Battle Smith with a gun that has a Steel Defender that looks like a Nimblewright would fit in the Forgotten Realms. Or if they reflavored their blasting spells as Smokepowder, an Artillerist could fit.
Except they absolutely DO NOT.
They find an existing suit of specific magical armour and make it More Magicker. Or existing suit of armour period. There's no design, no creation.
"Design" is flavoring the mechanics of the class/subclass, which is explicitly encouraged in the class. The Armorer has different "models" of their Arcane Armor that they can customize with infusions. The subclass says "your metallurgic pursuits have led to you making armor a conduit for your magic". They are designing armor that channels their magic in different styles, which they can modify in multiple ways. The mechanics are a simplification of the "research" process, just like wizards automatically receiving new spells in their spellbook is a simplification of them discovering how to access higher level magic.
I didn't say it was "sci-fi", did I?
I said it didn't fit. It doesn't fit because it's ultra-heavy-duty magitech, not "sci-fi". It turns Dragon's Dogma into Final Fantasy 13. That's fine if you want to run Final Fantasy 13, but if you want to run Dragon's Dogma, it doesn't work.
Apologies if you didn't mean sci-fi, I guess I misread your "it doesn't fit a popular
fantasy archetype" post from earlier. I thought you were implying with the italicization that there was another genre that artificers are better for (and people commonly complain that they're "too sci-fi for D&D").
This is just beneath you, dude.
Many classes in 5E have basically no options, or no real trap options. A mediocre subclass is not a trap option, so that's most classes in D&D already out as not having trap options. No Divine caster has any trap options because they get all spells. So they're out too. What does that leave us, Arcane casters? Except Wizards, Sorcerers, and Bards get enough spells and a good enough spell list it's almost impossible to trap yourself - and they don't have anything like Infusions or the magic-item-simulator stuff.
Martial characters choose their subclass, combat-enhancing feats/ASIs, and fighting styles (except barbarians). Battle Masters get to choose maneuvers, too. There are "trap" fighting styles (Great Weapon Fighting and Protection come to mind), trap feats (Savage Attacker, for example), and trap subclasses (Battlerager and Berserker Barbarian, Purple Dragon Knight, Arcane Archer, and Champion Fighters, Way of the Four Elements Monks, PHB Ranger subclasses)
I would challenge you to actually argue that "arguable", because I don't think it is.
Warlocks are far more obvious - for starters all their choices are openly and obviously presented to them, which is flatly not the case for Artificers.
And to be a "good Warlock" you need two things - Eldritch Blast and Agonizing Blast. Boom, done, you're great. You don't need any system mastery. After that the differences are small. That is not true at all with Artificers. And certainly no other class is even arguable.
That's only if you know how good Agonizing Blast is. Which requires familiarity with the system. Pact of the Blade is a trap option, the Eldritch Invocations that give you a spell you can cast once a day with a spell slot are traps compared to many other options, and some of the subclasses are bad (Undying is the most egregious). And with how few spells Warlocks get to learn/cast, some of the spell options are traps, too.
The optimal option for different Artificer subclasses is just as simple as "Eldritch Blast and Agonizing Blast". Battle Smiths need one of the Magic Weapon infusions, and they're good. Armorers need armor-increasing ones and eventually a magic weapon one, and they're good. Alchemists and Artillerists need an Enhanced Arcane Focus, and they're good. 1-2 infusions required to be as optimal in your role as the Warlock is in the Eldritch Blast spamming.
