I think you mean 100% by consistently and generalization and I mean typically or more often than not, when using them.
No I mean what I said. When talking about classes and damage I think it is difficult to come up with a generalization that applies "more often than not" in a one-shot and I think it is impossible in a campaign that covers multiple levels.
If you laid down specific assumptions you could perhaps do this effectively, but then it would only apply in those narrow bounds which by their very existence rule out the typical game.
And that PC has given up strong ranged options by using the shield.
Truestrike is pretty darn strong with a pistol as an opener in combat. After that it is assumed you close.
Also A Palding with a Javelin and Divine Smite is pretty strong but an even better option most of the time is Wrathful Smite with a Javelin, although in the Whiteroom it is less DPR.
You've given up alot of damage by using your fighting style for defense and being limited to at most a d8 weapon due to defensive duelist. Just like I claimed would happen. You do 2d8+8 damage = 17 per turn.
At 5th level, not counting Hunter's Mark, not counting Divine smite, not counting Vex, not counting Rage, no counting any subclass ablities .....
Factoring in the typical 60% chance to hit and you are at 10.2 DPR.
No it isn't. Even going with a simple Rapier, factoring in a 60% chance and Vex it is higher than that. How much higher depends on the number of foes, the length of combat and the amount of time attacking one foe. The upper limit with a 60% base chance to hit with no advantage and Vex will approach 15 DPR including crits in combat against a single foe for an unlimited number of rounds. Fighting Goblins, yes it will be capped at less, but that 25 hp fireball the Wizard throws on 7hp Goblins will be capped as well.
If you go strict RAW cheese to maximize damage you would go Vex-Nick-Vex with a Shortsword-Scimitar-shortsword while holding a shield. As an alternative a fighter can go Sap-nick-Vex with Longsword-Scimitar-Shortsword and give the bad guy disadvantage on his first attack to boot, way outshining a caster in terms of defense..
Finally in 2024 you can play any small character as a Sword and Board with a Lance and get GWM and topple, again making many attacks with advantage AND adding GWM damage. You lose defensive duelist doing this, but I've seen this done with a Ranger and medium beast mount and if you get dismounted you go to a back up 1d8 weapon. RAW though you can do berrer as you could just as easily climb on to the back of another PC and keep using your Lance.
I have never seen players play these builds with sword and board nick or sword and sword board lance-GWM from an allies back, but in a whiteroom they are as valid as any other build.
These examples are all RAW at 5th level and do not include things like Rage, hunter's Mark, Divine Smite, subclass abilities etc.
Ultimately the defensive duelist martial PC you describe here is just not going to be very effective.
But if we are speaking in generalities he is going to generally outdamage most full casters in play, whether or not his numbers in the whiteroom are better.
The monk looks alot better for this. Alot more damage, mobility, ranged potential. Good control options. Grappler is an amazing option. The only downside is the base monk will still feel a little squishy because 17 AC and d8 hp isn't great for a melee character, even with a good reaction single hit damage reduction ability. Mercy Monks healing seems like a potential solve for that though. The fighter dip for 2nd wind, sap (spear) mastery and dueling fighting style seems like a particularly great addition.
Deflect attacks usually means the first attack that hits does not damage you at all and the 17AC is less squishy if foes are regularly attacking with disadvantage.
I am also not using a Mercy Monk. I am using a Drunken Master/Scout, currently level 5/7 (was level 5/1 in the example I gave).
Drunken Master is great with the 2024 rules and grappler feat because of the free disengage and +10 move you get with FOB. This allows you to grapple and prone and enemy and drag him out of combat at full speed to where you can murder him. My Rogue subclass is Scout which lets me move off turn any time I have someone grappled and don't use my reaction for something else.
The thing is both of those subclasses (Drunken Master and Scout) are pretty weak but the synergy between the two of them and with the new Monk abilities, Cunning Strike and the new Grappler feat is awesome and that is an example of why you can't really speak in generalities easily, because the generality would be these are weak subclasses.
I am playing that character in part because another player jokingly asked me to play an actual non-caster in the next campaign. I compromised and asked for Magic Initiate, but I had to dig deep to put together all those synergies in a character that fit my play style without any spell slots. When I had to skip part of a session, my DM said the character was
"too complex for anyone else to play" and they just had her gone while I was gone. This is even though it is the lowest magic-using character I have played in a long time.