Blade ward with your 16 DEX still means 14 CON.
If you are rolling that depends on your rolls but on point buy you can do 16 Dex and 16 Con and Bladeward is a Warlock Cantrip.
In fact I would dump Charisma if I was purposely building a max-durability 1st level PC. Here is the point-buy array I would use:
S12 D16 C16 I8 W14 CH8
Goblin minions and kobolds with their +4 to hit will hit that approximately 1 out of 3 attacks and approximately 1 out of 3 hits will break concentration dropping blade ward.
1 in 3 will not hit and even if it was, this is 9 attacks. How many attacks do you think a 1st level character attacking from range is going to take before advancing to level 2?
On a lucky day 1 in 10 incoming attacks would cost the warlock both durability and damage.
Not considering the shield spell and not considering enemies being poisoned or scared. Add those and it is more like 1 in 15 or 20 which is more attacks than he can expect to take at 1st level
The damage is 4 points from those attacks. The warlock with 10 HP and 5thp takes 4 hits to drop and cannot recover HP or tho during combat.
Yes, so gues your point is he won't drop.
4 hits is 12 attacks by your flawed math, more like 20 attacks in play .... which is more than a 1sst level character will typically take between rests.
The fighter doesn't lose AC from lost concentration. The fighter gets hit less often before accounting for disadvantage.
The fighter can't poison or scare enemies either and is in or close melee to have decent damage, where he is taking a lot more attacks.
The fighter with 15 HP would also take 4 hits to drop, but after 2 hits spends a bonus action to recover 6.5 HP, takes 2 more hits and spends another bonus action to recover 6.5 HP, and then takes another 3 hits before hitting 0 HP.
You are not considering the shield spell. Chances are when it comes to those first two hits, one of them missed the Warlock. Possibly both of them missed the Warlock
The warlock would need to rest after 3 hits,
yes after 3 hits .... which is going to take on the order of 15 attacks ... or about all the time spent adventuring at 1st level.
The fighter would need to rest after taking 6 hits.
Which is going to come a lot faster than the 4 hits (3 + shielded one) the Warlock needs to suffer.
I'm not seeing the warlock advantage here.
The Warlock's advantages are as follows (in relative order of importance):
1. Has more total hit points at start of day (casting False Life)
2. Primarily attacks from range, and when forced into melee regularly puts opponents at disadvantage from poison or scare (Quasit).
3. Can cast shield spell killing at least one hit per day.
4. Can cast another shield spell every time they short rest (or Armor of Agathys if they need that instead).
The intent of this thread was to explore the most durable 1st level PC that still did decent damage. It is all situational, but I reject the notion that durability is just about static AC, hit points and healing available. It is more about tactics and employment than it is any of those and things that afford such options while still being competitive in terms of the basic numbers will generally be more effective IMO. Without any other specific defining terms or assumptions I stand by what I said earler - a Dwarf Warlock with Magic Initiate feat because I think that build offers the most durability. It does not offer the most hit points, it does not offer the best AC, it is not the best tank, but I think it is generally the most durable, or at least the most durable build I can think of using the 2024 rules.