My general thoughts:
Lands - Seems like budget isn't much of a consideration for the deck, so I would cut lands that enter tapped and/or don't have a sub-type, out go
Bloodfell Caves,
Golgari Rot Farm,
Gruul Turf,
Rakdos Carnarium,
Darigaaz's Caldera, and also
Rogue's Passage is out because you WANT your commander to be blocked for those triggers. If it were me, I'd put in some basic lands. If someone plays a
Blood Moon on turn 2 or 3 your game is over.
Urza's Saga to go find that
Shadowspear. A lot of your lands enter untapped IF you control forests, mountains, swamps, so more of those sub-types the better to let your duel lands enter untapped. Overall, your land count seems a touch low also, but if you are ramping enough and drawing enough cards it doesn't seem like a big issue, but I would probably try and add like 3 more lands and get your total to 38.
Artifacts - I notice you state that equipment decks aren't really your thing, but the fact that is what it sounds like you are trying to make I feel like you are a bit light on actual equipment. As far as equipment you already have, I would just mention be careful about the Swords. Obviously SoFF is REALLY good, so I'm not gonna say take that one out, but as for SoFI and any others you contemplate, keep in mind if your Commander has protection from too many colors then your opponents can't block it, and thus you won't get your fun triggers.
Mithril Coat is up to you. Commander is already indestruct on your turn, is it worth a slot for making it always? I'm not so sure. I've never thought the 8 mana (3B) for
Vorpal sword was worth it and 3B might be surprisingly hard to come up with in a 3 color deck. Maybe not. Anduril, Flame of the West do you really need 2 1/1's? I don't think this advances your game.
Nemesis Mask all-star for the deck. If it were my deck, I would lean into Deathtouch and Trample which it seems you have a good amount of. Assigning 2 damage to each blocker if you have deathtouch (and if they aren't indestructible) results in triggering your Commander. There are lots of equipment that grant these abilities
Shadowspear,
Sword of Vengeance,
Haunted Cloak,
Embercleave,
Tenza, Godo's Maul,
Blazing Sunsteel could have some very fun tricks,
Kaldra Compleat. I would also think about adding
Blackblade Reforged to ensure you always have the beefiest hitter even against the toughest blockers.
Hammer of Nazahn makes your Commander always indestructible and pay the equip cost of all other equipment for free. You say you want to be oppressive, nothing is more oppressive than
Worldslayer,
Grafted Exoskeleton could also be 1 hit kills for your Commander, as well as anything that gives double strike.
Darksteel Forge if your playgroup learns to start blowing up your toys.
Enchantments - The ones you have are a little all over the board, but all are good in the deck, although personally I'm not really into the Umbra's.
Bear Umbra for the untap is good, but the others don't seem good enough to me.
Spider Umbra especially you don't have much
Vigilance and you are attacking with your Commander, what good does reach do you?
Boar Umbra just not enough.
Spider Umbra, I guess if you are playing the deck and not drawing enough cards to play but I think there are MUCH better draw spells in
Jund colors. Good to add are
Unnatural Growth,
Rune of Might or
Rune of Mortality to lean into deathtouch and trample,
Colossal Majesty should trigger for you most turns,
Gift of the Deity for repeatable
lure effect,
Deathreap Ritual is a value machine.
Instants - A lot of this is up to your style, but mostly I like what I'm seeing. I love the fight cards. I would say, it feels like you may be a bit heavy on them, maybe keep 3-6 of your favorite, cut the others to add more lands and equipment.
Fog? I guess if you think you need it.
Back for More doesn't do it for me personally. Much more efficient ways to get something from your GY in your colors, I don't think getting the immediate fight makes it worth 6 mana. I would think about adding a couple more ways to deal with opponents Artifacts and Enchantments. A
Meekstone or
Pacifism effect shuts you down. You have SO many good choices in Green,
Beast Within seems especially good for you as you take the thing that has locked you down and make it into a creature that has to block you and trigger your ability.
Chaos Warp,
Assassin's Trophy,
Krosan Grip,
Golgari Charm if you like options.
Sorceries -
Chandra's Ignition another all-star for the deck. I guess you really like Tutoring and Fighting, a lot of duplication here. I would again cut some here for other cards previously mentioned. I love the versatility of
Dig Up if tutoring is a big part of your gameplan. It's 1 mana to find a basic land you need early on, or a Tutor later.
Reanimate can bring back your Commander MUCH cheaper than previously mentioned
Back for More, it can also be used to grab a big scary creature from an opponents graveyard that you killed with your Commander attacking and they had to block and die.
Spinning Wheel Kick might be one of the best fight cards you can have for this deck (Chandra's not withstanding). I would get some ramp cards in like
Farseek,
Nature's Lore,
Three Visits, keep
Bushwhack in only if you decide to add some Basic Lands (because currently you have none) as one of your 3-6 fight cards.
Jeska's Will is a red staple and it's very good. Overloading a
Vandalblast before you go to combat with your commander probably gives you a LOT better targets for your trigger in the world of artifact tokens (like
treasure or food) that we live in.
Creatures - I don't have much, I think you have a lot of great choices here IMHO. Personally I think
Surrak and Goreclaw, and
Goreclaw, Terror of Qal Sisma don't do enough in the deck.
General Marhault Elsdragon puts in way more work than your
Boar Umbra,
Toralf, God of Fury seems to synergize very well with what you already want to do.
Heiko Yamazaki, the General to bring back equipment you have that are getting blown up? Just spitballing, unless you really want to lean even more into extra combats with those types of red creatures, again I like what you have.
I guess I would try and give you some advice as I see it by asking a few questions.
1. You say you want the deck to be oppressive, what does that mean to you, and your playgroup? Do you want high damage output / evasion on the commander / extra combats to end games quickly to play more games? Do you want to play Stax style where you are locking out your opponents and keeping their boards clear, toy with them? Do you want to make them have to play around your attacking Commander by not being able to slam all their creatures down?
2. Is there any style of play or deck type that your playgroup doesn't allow? Or is this play as good as stuff as you can and see who comes out on top?
3. How do you enjoy playing, what's your style? To win? To win fast? To do cool things? Combos? Draw all the cards? Open to anything?