As a 443 EK myself I will tell you what upgrades you can make, since you don't have any BiS items, I would go the following route:
Hunts for profit -> Werelions, Carnivors and Furies on Oramond. Those are the ones that I remember.
You can also hunt Asuras (and get one of the best experience there for that level range).
As for items upgrades:
Upgrade Guardian Boots to Depth Calcei or Frostwalker Boots -> Both have 5% physical protection, which is 3% more than Guardian and also doesn't have the -2% holy protection decrease, which is one of the main damages on Werelions. Frostflower also gives you 5% protection against Ice, this is useful on Nagas and Winter Court Elves.
Then improve Prismatic Armor to Falcon Plate as soon as possible. You have only 5% physical damage reduction with Prismatic and only 1 imbuement slot, that means you can't imbue it with a Death protection imbuement (one of Nagas main source of damage). Those hunts you say you are struggling are also because you have little physical defense reduction. Falcon Plate increases your physical protection to +12%, 1% less than BiS Spiritthorn Armor, so it's 7% more physical protection than Prismatic Armor. It also has 2 imbuement slots and you can imbue Vampirism and Death Protection (useful against Nagas).
Even if you get Spiritthorn Armor later, Falcon is still great to have as a secondary option thinking about elemental protection imbuements swap.
Then I would go for Falcon Greaves, as Fabulous Legs gives only 4% Physical protection, while Falcon gives 7% and also +1 skill than Fabulous. You also get 7% Ice Protection which is, again, useful against Nagas and Winter Court Elves and any Ice damage hunt.
Terra Helmet is fine, it's a good helmet and you don't need to switch it that fast. More skill is nice, but the other pieces of equipment are more in need of an upgrade than the helmet.
After all those improvements, you also need to improve damage as it contributes to life leech, meaning you get more survivability, so..
Soulshredder -> 3 Imbuements, high damage and a must. This is the first weapon you should try to get as it improves A LOT your character. Ice damage is NOT good at Nagas (they take only 80% of the damage), but it will be great on other hunts.
If by any chance you get to level 600, then you should also go for Sanguine Razor, it's the best weapon against Nagas as they take a lot of Energy damage.
Always prefer Two-handed weapons, the low damage that you inflict on hunts is what makes you be in danger more often, as you don't have enough damage output to kill boxes fast and also means you have less life leech.
1) Guardian Boots -> Depth Calcei/Frostflower Boots
2) Prismatic Armor -> Falcon Plate
3) Fabulous Legs -> Falcon Greaves
4) One-handed Weapons -> Two-handed Weapons (preferably BiS like Soulshredder and Sanguine Razor)
5) BiS items: Spiritthorn Helmet or Spiritthorn Armor > Spiritthorn Ring > Pair of Soulwalkers > Sanguine Legs
Helmet and Armor makes a huge impact as they have reflect damage, also high protections and high skill gains.
Ring is also a game changer for EKs, but you need to balance if it's worth it to keep enchanting them with Silver Tokens on determined hunts. Some are not worth it with low profit, and you should consider using Red Plasma Rings.
As for Soulwalkers and Sanguine Legs, they are very expensive, both are top tier equipments, with Sanguine Legs being the most expensive EK item. If you don't have problem with money, you can get it in any order, I only suggested Helmet first since it's the weakest after the upgrade of all other gear. But you can choose Armor, Ring, Boots and also Legs.
Going first for the Legs means you will keep farming it for a long time without other items, so I prefer going for the cheapest first and the expensive ones later. It's up to you.
