Elden Ring Patch 1.08 Colosseum DLC – 1st TIME TRYING PvP!

I’m like a 300 and been sitting in the lobby just trying to get into a match

12:53 "I feel like I'm taking way more damage from people than damage I'm dishing out"
25:08 "I don't know what's going on and I'm like not dealing damage to people"
Unsolicited advice incoming, if you're happy with your build and you don't want to change any of it just ignore this
From a quick glance at your stat spread, I'd say your build suffers from a common problem among PVE builds that can be summarized as "lack of focus"
Frozen Needle, one-handed Keen Omencleaver, Reduvia, and all of that with 44 poise on medium rolls. The first thing I would address is your weapon selection; currently it's reaching too far in different directions. Trying to make a stat spread that appeals to all three of these weapons is not something you can do at your level and get good damage out of all of them. At the moment your dexterity is your highest stat, so for this example I'll assume that you would want to just make this a melee dex build. That would ultimately mean dropping Reduvia, but if you want a ranged option, we can address that later. Let's go through each stat individually and see what we can cut.
Vigor: it's at 60, and it should stay at 60. nothing to change here.
Mind: Unless you need all of that FP to hit a breakpoint for a spirit ash or something, 17 mind is way more than you need for a melee build. Drop it to base level.
Endurance: This one is trickier, as it largely depends on your equipment. Fat rolling is out of the question, so we need at least as much as is needed to medium roll with your heaviest loadout. I assume your current outfit is your preferred fashion, so assuming that won't change, your heaviest weapon option is the omencleaver, the total weight of which when combined with your armor appears to be 46.3. Your current maximum equipload is 73, which is WAY more than you need for the 70% breakpoint. 67 maximum load will give you medium rolls with that weight, so you can drop endurance until you hit that number.
Strength: You're a dex build, you don't need more strength than is necessary to wield your weapons. Since you tend not to use your offhand for much, there's no reason not to two-hand your weapons at all times unless you like the one-handed moveset enough to justify the lack of poise damage. Assuming Omencleaver is still on the menu, you don't need 20 strength at all, ESPECIALLY if it's keen infused, you only need 14 so that the 50% effective strength increase for two-handing brings you to the strength requirement to wield it, so reduce points in that.
Dex: Ignore this for now, we'll be pumping this full of all the extra points we're squeezing out of your other stats at the end.
Intelligence: Appears to be base level, ignore.
Faith: As above.
Arcane: I assume points were invested for the sake of Reduvia. Trying to cater to an arcane weapon with points spread this thin does not pay off. Arcane doesn't scale the frost buildup of Frozen Needle or Cold infused weapons. Drop points to base level.
All of the extra points you get by cutting the chaff out of your other stats should all be dumped into Dexterity. Let's assume you can reach at least 60 with these points. That's good, but we can do better.
Your Talismans are… suboptimal. Starting with the physical dragoncrest, while I'm sure you already understand that all of the damage reduction talismans have separate numbers for PVP and are FAR less effective against players, the actual numbers might surprise you. That talisman is only giving you 4% bonus physical negation. Absolutely not worth it, remove. the two stamina talismans are also not worth it. As you practice, proper stamina management will negate the need for these entirely. As for the Crimson Seed Talisman… Honestly I can see a case for it in the colosseum, especially with only one flask, so if you want to you can keep that one. But now we have three slots to work with. First things first, Prosthesis-Wearer's Heirloom (Ideally it would actually be Millicent's Prosthesis, but the Heirloom is far more accessible) for more damage. The real soft cap for diminishing returns on Dexterity is 80, so getting closer to that is worth it. Your poise is a little low at 44, but the Bull-Goat's talisman can help shore that up and let you poise through more things even while wielding your Frozen Needle and take favorable trades. That last slot could be a lot of things, Crimson Amber +2 for generic safety, Shard of Alexander for ash of war damage, Great Jar Arsenal so that you can drop even more points from endurance to put into dexterity, Stalwart Horn Charm to help resist bleed and frost procs, or perhaps the Blue-Feathered Branch Sword to occasionally let you win otherwise lethal trades.
Now on to your Physick. From what I saw it looks like you have the HP regen and Stam regen tears, and these are fine for general use, but for the colusseum I could recommend some better things. +10 Dexterity from the Dexterity-Knot Tear should go without saying; It will help you reach that 80 soft cap and improve your damage. The other tear could be something defensive, I personally like Crimson Bubbletear for effectively 30% more hitpoints assuming you don't get oneshot, Windy Crystal tears for those insane fast-rolls so that you aren't held back by your low poise combined with medium rolls, or maybe even the Speckled Hardtear if you find yourself running into a lot of status builds. Whichever you decide, I think the +10 Dexterity is pretty mandatory to shore up your damage. Let's run some numbers real quick. With your current stat-spread of 20 strength and 42 dexterity, your keen omen cleaver has an AR of 573, rather low for this level bracket, especially for a curved greatsword. However, with the stat efficiencies allocated, the new talismans, and the +10 dex physick, it would be possible to reach 80 dexterity, raising your AR from 573 to 690, more than 20% extra damage before we even take into account how a higher raw AR better overcomes your enemy's defenses, and the only thing you sacrificed to get it was cutting Reduvia out of your build. Your Frozen Needle would go from 391 to 463, too. Still a bit low, even for a rapier, but I assume you want to use it for the R2 projectile and because it's cool.
With those changes, you will hit harder and take more punishment, hopefully closing the gap between you and the other guys. If you miss the Reduvia for it's bloody slash ash of war, you can get that ash of war and put it on other weapons, like a keen-infused sword for example so you can still have that bloody projectile and not have it strapped to a dagger that deals almost no damage.

This comment is getting a little long so I won't get into more niche stuff like consumables, but just know that there's a lot you can do to improve your build without sacrificing its identity. Have fun!

Imagine healing in a duel