Firstly, by "same boat", I meant that both characters are relatively unknown to the general public. If you were to ask random people who Heavy was from TF2, most would look at you cockeyed. This isn't the case with household names like Mario, Sonic, several of the Pokemon, etc.
As for Heavy's supposed "iconic" status, your bias here is pretty hilarious. I mean, the character doesn't even have a proper name FFS. The characters from Overwatch are much more well known and distinguished in the "hero" shooter genre, and this is FACT. If it wasn't, you would have had Heavy in Ready Player One instead of Tracer, etc. It doesn't matter if the last update to TF2 was three years ago, Heavy is not "iconic" outside of those that played his game and especially not within the Smash fanbase which brings me to my next point.
The SMASH fanbase. The very fact that so many people within Smash speculation are scratching their heads over Heavy is proof that the general Smash base never really thought much of him. Now, people on here have talked about the sometimes sheltered nature of the "smash bubble", but I'd like to point out that it's that smash bubble that Sakurai and his team are most interested in appealing to. Not a bunch of randos online that think a dude with a minigun would make for a good smash character. I love how people are always so hellbent on a particular character that they never even consider what it would be like to actually PLAY said character in Smash. Think about it. If Heavy were to be a character, he'd be a big, slow *ahem* heavy whose primary method of fighting would be simply spam machine gun fire at people. Yeah, not exactly the most colorful addition.
Now let's look at Geno. He heralded arguably the best and most unique Mario RPG spin-off ever made. His entire body is a swiss army knife of guns and weapons including finger bullets, rocket arms, elbow cannons, star guns and a wide assortment of flashy energy attacks. Then throw in a smaller frame and higher speed and you've got yourself a formidable zoner. Sure he was from only one game released in 1996, but remember that "Smash bubble"? He's got a significant following within Smash fandom and Sakurai/Nintendo KNOW IT. The fact that Geno has already earned himself a Mii costume and a spirit is further proof of that. Let me ask you, what TF2 spirits exist in Smash Ultimate? How about ATs? Costumes? Where was Heavy on the official Smash ballot? Yeah, if you've got a thing for Heavy, all power to you, but don't question my understanding of "obscure" when you haven't got a clue.
I really don't think that Geno is more iconic than the Heavy. Just because Geno has a greater Smash following doesn't make him more iconic. Heavy is the mascot for TF2, a game with incredible influence, thousands upon thousands of fan SFM and Gmod videos, an incredibly dedicated community that is keeping the game semi-alive through sheer force of will, and an average of over 60,000 players
at any given time. You argue that Heavy isn't iconic to those outside his playerbase, which isn't true as Team Fortress is still an iconic FPS series (it's made by Valve, they only make gold.) but even if it was Geno certainly isn't, as his game was from 24 years ago and he hasn't made a playable appearance since then. He's not iconic in any way apart from being a hugely popular Smash request.
You also talk about Heavy having no moveset potential which just isn't true. Outside of his wide array of miniguns, he has his shotguns, several foods that either heal him or buff his damage, and a ludicrous array of melee weapons, including but not limited to:
-His huge muscly fists.
-Bear paws that heal him on hit.
-Holiday mittens that force the opponent to taunt.
-Boxing gloves that increase his damage significantly when he gets a kill with them.
-Boxing gloves that make him move a good bit faster at the cost of damage.
-Ham.
Even if that's not enough they could do what they did for the Belmonts and have him borrow a few moves that don't break character:
-He could drink some of Scout's Bonk! Atomic Punch or Crit-a-Cola to buff himself.
-Pyro's Flare Gun is a possibility, a weak projectile that does lasting damage.
-Borrow some of the Sniper's Jarate to debuff the enemy like Inkling.
-If you want to get kinda crazy he could pop an Über canteen from MvM and turn invincible for a few seconds.
-Besides that he would have tauntkills, which are hilarious.
I get that Geno is your number one (same as me), but please don't try to drag down other characters to make him look better.
