Curious why you like it more than Tusk? I think Tusk outclasses it pretty decently for the most part when it comes to typing, the only benefit for Treads is it's speed tier and access to Volt Switch.
4 weaknesses vs 6, more resistances too. Higher bulk, especially on special side, reminds me of ORAS Drill. Immune to Toxic, so can switch into the rising Pex for free (Surf does 0). Actually consistent vs no Focus Blast Gholdengo. Steel typing is rare too, while there are many common fight Mons like Breloom, Slither Wing, Pawmot, Tauros and Iron Hands. The Mons I would be using Tusk to check are easily checked by other Mons, therefore if I use Tusk, it's for the offensive potential, while Threads is a better supporter. There are more reasons, but the main one is Threads being more comfy for me to fit into teams than Tusk, which actually requires brain to build with.
One thing in Tusk's favor is that his typing is a LOT better suited to what's big in the Meta right now. Tusk easily wins in Physical Bulk, while it takes ~5% more from something neutral like Specs Dragapault Shadow Ball as a random neutral hit when compared to Treads (assuming the either 0 or max HP), meaning their typings are the majority contribution to their defensive profiles vs the other. Treads definitely has several resistances and immunities over Tusk, but in practice I feel like Tusk gets further in OU considering their neutral and weakness profiles, which matter a lot more on Pokemon with such great natural bulk.
First and foremost, Treads has to contend with a Weakness to Ground and to Fighting, which are definitely prevalent in OU right now (Eeveeto himself even noting several common Fighting types in OU on top of Tusk being high usage). Meanwhile while he has several good resistances, current OU feels very sparse for Flying offense (other than Roaring Moon, most seem to use it defensively rather than offensively) and the only offensive Fairy presences right now are Iron Valiant (who can still carry FB or Close Combat as common coverage), then Hatterene and Azumarill at more distant seconds (Hat for its more Magic Bounce Supporting role and Azu simply being much less common plus Water STAB). The Steel Typing also doesn't do it many favors against Garg, even if it's a winning match-up on Tera-Fairy vs Tusk, with the higher Salt Cure chip and that thing being a very common defensive fixture. And while its typing is good in and of itself, it can lead to weakness stacking/needing to forgo Pokemon like Gholdengo, Corviknight, and Ting-Lu (mainly Fighting), excluding Tera users who either gain or lose shared weaknesses like Tera-Fairy Garg/Dirge or Tera-Grass Volcarona.
In a Meta like Gen 8's with things like Tapu Lele and Koko (even without Quark Drive benefit), Dual Wingbeat D-Nite, Torn-T, and Clefable running around, Treads would be eating phenomenally, but the state of current SV OU doesn't give it enough to leverage its excellent typing against compared to its counterpart as a Bulky Ground Glue or Gholdengo as a versatile Part-Steel utility Pokemon, though no denying a fast Volt Switch on something like him has its merits. I definitely expect him to pick up if we start getting more good Fairies and such from Home/DLC like, some prior mentions, Enamorus, and Magearna if it stays OU, but with the roster we have right now, Tusk is incredibly stiff as competition.
Offensively, Tusk is also blessed with easy access to strong main STABs for almost any set it tries: Headlong vs EQ is a Power vs defensive consistency choice, and Body Press gives something like BU Tusk another consistent Damage option without compromising the defensive boosts either. Treads by comparison has the standard EQ, but otherwise has Iron Head for Steel STAB given its Signature Steel Roller doesn't work in any scenario where you'd want it to (i.e. ripping up Terrain on a QD mon or failing otherwise). Treads is faster, but this combined with his lower offensive stats than Tusk means he's a lot more dependent on his defensive profile resisting or blanking hits to get turns for his utility rather than threatening as many neutral targets into fleeing and letting him act, which as my previous paragraph discussed isn't something the current OU does favors for.
Iron Treads I wouldn't call slept on because we have a fairly good picture of what it does well, but the meta we have now compared to one potentially forthcoming simply doesn't favor the Wheel over the Mastodon.