Enshrouded Korthos - DnD 5e, 2024 - with adjustments for incompetence on my part.

"This is going to be tough," whispers  Vespera to the others. 

Is the armored knight still moving and clanking, or has it stopped to watch the door?

Manny, feel a bit skittish, gets his feet planted to fire an EB, Below the waist Manny is set, but above the waist he is relaxed, arms at his side, shoulders slack.

At the moment the knight is just facing you and the door as you go in. (ooc - Not enough time has passed, unless you skip your turns)

Silverlining slowly enters the chamber, ready to deflect an attack that might come. Once again, unaccustomed to undead beings (and unsure this is the dead), he speaks a few words. 
“Well are looking for a key to a different vault here. Can you assist us in its location?”

The Knight looks at Silver, raises the shield in one hand and the sword in the other and starts to go around the central sarcophagus and towards Silver. 

Manny being wary, gets his arms up to assist Silver with an EB, taking care to make sure he does not hit Silver if the Knight appears to make an attack.

Insight on the Knight 5

Perception 19

Vespera will prepare  her daggers, ready to dart into the room and unleash multiple attacks if the armor figure attacks.

(please let me know exactly how your 3 characters and the Imp are situated near the door.)

The Knight moves step by step around the sarcophagus, eventually reaches Silver at the door and swings at him. (prepared actions tactics, strategy etc can take place now)

Manny was flanking Silver so that if he fired, he would have a clear shot at the knight.  Manny was measuring the angles much like a footballer would when he has a defender to his front and a teammate to the side so that when he kicked, it would not be blocked by either person.

If needed Initiative 13

The imp went invisible and is flying high cover looking and scouting for anything suspicious

Imp Perception 2

Insight on the knight 7

Vespera was waiting in the doorway. When the armor attacked, she would move into the room to a flanking position, attack it twice with advantage, then as a bonus action disengage, and use the rest of her movement to move away from it.

Thats more than can be done as a prepared action, so I figure it will be her first action in the initiative order after the undead goes.

Silverlining was inside the room. As the knight moved towards him, he would have shifted away from the door to allow space for others to access the knight and the room. (He doesn’t back out of the room, he’s not retreating)

He takes a defensive stance (dodge action). 

Manny and Vespera open the door and  the Knight is revealed, Silver steps forward gets its attention by speaking to it. The Knight approaches. Vespera steps to the side, planning to flank, attack and then move in the room, behind the Knight. The Imp is stays above the Knight scanning the room. Silver is ready to take on the Knight. Manny is ready to blast. 

Vespera attacks twice, flanking the Knight. (roll the attacks and dmg)

Manny blasts his eldritch energies. (roll the attacks and damage)

The Knight swings at Silver, either ignoring or not seeing the other at all. (Attack: 5) (Damage: 3) Silver easily dodges the swing. 

(You all have three turns now, 1st the one that was "readied", then your initiatives,(knight's initiative is 1) then Knight just swing and missed so now its your turn again)

Manny fires an EB when readied Attack: 11 Damage: 12

At Initiative 23 ... Attack: 8 Damage: 14

second round Attack: 10 Damage: 11

Round 1, ready short sword and dagger

Round 2: move to flank, attack with both dagger then short sword (single action due to nick) with sneak attack damage on the first hit, bonus action to disengage, rest of movement to move away from undead.
Attack dagger: 16 Damage: 6
Attack shortsword: 24 Damage: 5
Sneak attack damage: 1

Round 3: Repeat: move to flank, attack with both dagger then short sword (single action due to nick) with sneak attack damage on the first hit, bonus action to disengage, rest of movement to move away from undead.
Attack dagger: 20 Damage: 5
Attack shortsword: 9 Damage: 6
Sneak attack damage: 6

Silverlining was playing a very defensive position in this fight, keeping the knight occupied to allow the others to attack. 

Readied action: Dodge

Rnd 1:  Attack, To Hit: 10. 
Bonus Action: Attack; To Hit:  5

Rnd 2:  Taking the dodge action again. (Disadvantage to attacks). 

Manny notices that the eldritch blasts seem to dissipate somewhat on such a heavy armor. 

Vespera has a sinking feeling seeing mostly sparks from her hits on the armor or shield. Even the hit she did in one of the joints did not seem to weaken whatever is inside in any discernible way. 

With all the people rushing about Silver, one from this side, one from the other and the freaking door in the way from behind, he could not really put enough force in the first round of hits. He takes extra care to make sure the heavy armor knight does not get to hit him.

The Knight, uncaring it seems for its surroundings, the sparks from Vespera's blades or the thumps from the blasts, just swings at Silver, almost lazily. (Attack: 19) and (damage: 3)

Manny not sure what else is there as the blast is force damage and there is not much that can stop that, fires again an EB blast Attack: 18 Damage: 5

That last blast was a crit hit, the best i can do.  Manny looks on in anticipation due to he knows if this does not work, he is SOL.

The Knight does not seem to care for the blast it received from Manny and is already swinging again at Silver. (Vespera and Silver act before it on init i believe) 

Vespera will again try dagger and sword attacks, followed by retreating. She also cast a quick glance around the room to see if something like the key they are looking for is readily visible.

Move: partial move to flank
Dagger Attack: 19 Damage: 5
Nick Shortsword Attack: 17 Damage: Unable to parse dice roll.
Sneak Attack damage added to first hit: 3
Bonus action: disengage
Move: rest of move to move away
Perception to spot key: 22