Paladin ASI advice?

[emduck]

I'm playing an ancients paladin and we're approaching level 12.

Party contains: wizard, gwm bladelock, cbe/ss ranger/fighter, and tanky cleric. We're playing Out of the Abyss if that informs your judgment, but please no spoilers.

Currently the character is:

Mountain dwarf ancients paladin 11
16/10/18/10/12/16, Resilient (CON)
(No, I didn't buy that CON; we got +2 CON as a quest reward.)

I fight sword and board with a shield and a +2 weapon, defense fighting style (21 AC).

Multiclassing is probably not on the table; doesn't really fit the character. So please don't say hexblade.

I'm torn between STR and CHA.

In favor of strength--Obviously, smiting things is good, and you've got to hit things to smite them. But with two absolute damage machines in the party, raw damage isn't necessarily a niche that needs me. Athletics doesn't come up a ton because the warlock is stronger, but it's occasionally useful.

In favor of charisma--skills, save DC, and the aura. I don't use a ton of offensive spells. I probably spend about 2/3 of my spell slots on smites and 1/3 on spells, but usually not directly offensive ones--I'm concentrating on a buff spell pretty much every fight. I occasionally use Moonbeam on hordes of super weak mobs. Out of combat I use CHA skills quite a bit. And obviously, there's the aura, which frequently comes in handy.

Any thoughts?

[Blood of Gaea]

You've got a crossbow spamming Fighter/Ranger, a GWM Warlock, a tanky Cleric that likely knows/will know Spirit Guardians, and a Wizard that can keep a blasting spell or two handy. Your party has tones of damage output.

Definitely get Cha up to shore up those saving throws. Especially when you're likely going to have at least 2 other members (The Warlock and the Cleric) within range of your Aura.

+Cha is even more useful when you mention that you use those skills a lot out of combat.

[Aussiehams]

From your description of your groups playstyle, Cha sounds like the best option to me. You seem more like a support type, so lean into it. Maybe even look at Inspiring leader down the line if you max Cha.

[djreynolds]

Shield master might be helpful, dumping an opponent prone for you bladelock could be beneficial, and some help with a pseudo evasion

[CTurbo]

+2 Cha all the way if you're still at 16 now

[Corran]

Shield master might be helpful, dumping an opponent prone for you bladelock could be beneficial, and some help with a pseudo evasion
Though you run the risk of imposing disadvantage on the archer. Initiative will be crucial, and you cannot control initiative. That's why I would probably avoid shield master in this group. Don't forget that you can always shove in place of one of your attacks. Not ideal when you have IDS and each of your attacks hits for 2d8+5, so that's why shield master would make sense theoretically, but with this group composition, it's like 50-50 when shoving would be a good or a bad idea. The archer could just aim for the non-shoved enemy, but splitting dpr between multiple enemies is rarely a good idea.

@OP: How about sentinel? Fighting next to the warlock and the cleric means that you will get lots of reactionary attacks, at 2d8+5 damage (which is good damage for just one attack). And it's not like you have lots of other uses for your reaction. Aside from action economy optimization and a dpr boost, sentinel also draws a bit of aggro from the enemies. Meaning, that as things are, there is probably little reason for the enemies to prioritize your character over the warlock or the cleric. That is because you've got very high AC, and also because both of your allies are pumping out more damage than you. So sentinel gives the enemy more reason to target you, because if they don't, they get hit by your reactionary attack. Smite can act a bit like that, meaning that by smiting you force the enemy to think it's a good idea to focus you, but sentinel does pretty much the same thing without consuming spells slots, and in addition you can always continue to smite. Plus, a little more battlefield control (as sentinel OA's stop enemies from moving away, assuming you hit of course) never hurt anyone.
If you really want to pick between a +2 str and a +2 cha, I would go with the cha boost. Bosting your allies' saves and concentration (as well as increasing the DC of your CD and spells like moonbeam), seems more important to me than boosting your dpr by 5% or so. But I think that a feat like sentinel would serve you better.

[Guy Lombard-O]

You've got a crossbow spamming Fighter/Ranger, a GWM Warlock, a tanky Cleric that likely knows/will know Spirit Guardians, and a Wizard that can keep a blasting spell or two handy. Your party has tones of damage output.

Definitely get Cha up to shore up those saving throws. Especially when you're likely going to have at least 2 other members (The Warlock and the Cleric) within range of your Aura.

+Cha is even more useful when you mention that you use those skills a lot out of combat.

This. Also, the Cha bump will even help your concentration checks for those buff spells you're using.

[Keravath]

I'd also suggest bumping cha. The additional saving throw bonus for both you and your team mates is very worthwhile and from the sounds of it you have skills that you use that are cha based so your out of combat efficiency also increases. Ancients paladin is already defensive focused with the half-damage from spells aura so adding to that is building on your strengths especially when the rest of the party seems to have DPS covered (though to be honest, your DPS with improved divine smite as well as regular smites and spells is pretty good anyway).

[Mitsu]

I would go CHA to 18 and consider 1 level dip Warlock for Hexblade so you can use that CHA for attacks. After that just go for another +2 CHA and you are at 20 CHA which is also your attack and damage roll + you can other benefits of 1st level Warlock.

But definitely CHA.

[Waterdeep Merch]

Strength will be more helpful in most combat scenarios, though it's also pretty boring. Charisma will be helpful often in combat scenarios, and improves your versatility and teamwork functions.

Strength has a place in dungeon exploring, while Charisma makes you better at socializing.

You also don't actually need to cover anything. Your party's well-designed, with everyone's job being replaceable to some degree by another player. Well done!

Given that information, I'd pick Charisma just because it's more interactive and hence more fun.