Advice on 5e Paladin/Warlock

I’ve got an Aasimar Paladin 1/Celestial Warlock 3. RP-wise, he’s a paladin of Lathander who delved into his lineage to make a pact with a like-minded Solar. He’s got a kind of obsession with light (metaphorical and literal).

We’re sticking with published material mostly. My party is a fighter, a sorc, a wiz, a rogue, and a ranger, which makes me lean toward being healer/backup tank. I’ve already gone Celestial Tomelock, but I haven’t decided on an oath for the Paladin. I’m leaning toward Ancients or Redemption, but haven’t ruled out everything.

Starting Stats (point buy w/ DMG Aasimar):

Str 15 (to use plate)

Dex 10

Con 13

Int 10

Wis 9

Cha 17

I’ve been using alternations of Eldritch blast at range and Shillelagh/Green Flame Blade up close – pretty effective so far. I’m eyeing the possibility of Pole-arm Master, but still juggling with when to take feats vs ASI and if I want War Caster with it or instead (mostly for the shield AC). The next level is Warlock 4 and I’m thinking ASI for Cha and Con. I’m also considering that there won’t be much campaign left when I reach level 16/17, so usability along the way is probably more important that end-game optimization.

I’ve done some math on the DPR re: range/melee and stat choices, but it isn’t all the variations and I know DPR isn’t the only factor (nor is it my primary considering the other party members). Here’s the math on that, though:

5th level EB, Agonizing & Hex:
2d10 + 4(Ag) + 4(Ag) + 3.5(H) + 3.5(H) =
Average 26, 2 chances to crit (or miss)

5th level GFB, Shillelagh, & Hex:
1d8+1d8 + 4(CHA) + 3.5(H)= 16.5
w/ second enemy: add 1d8+3.5 = 8
Average 24.5 across 2 enemies

**At 6th level, GFB adds 2 dmg from Dueling Style, so 26.5 across 2 enemies

**Could get PAM at 8th, bringing it online well before EB can outclass it

11th Level (6War, 5 Pal) EB:
3d10 + 15(3xAg) + 10.5(3xH) =
Average 42, 3 chances to crit

GFB, Shillelagh:
3d8 + 5(CHA) + 3.5(H) + 5(Rad Soul) + 2(Duel) = 29 to 1 enemy
w/ second enemy: add 2d8 + 5 = 14
Average 43 across 2 enemies, only 1 chance to crit (or miss)

2 Attack, Shillelagh
1d8 + 5(CHA) + 3.5(H) + 2(Duel) = 15
1d8 + 5(CHA) + 3.5(H) + 2(Duel) = 15
Average 30, 2 chances to crit (or miss)

PAM alternative, 3 attacks, 1 less CHA
1d8 + 4(CHA) + 3.5(H) + 2(Duel) = 14
1d8 + 4(CHA) + 3.5(H) + 2(Duel) = 14
BA: 1d4 + 4(CHA) + 3.5(H) + 2(Duel) = 12
Average 40, 3 chances to crit (or miss)

17th Level (6War, 11 Pal) EB:
4d10 + 20(3xAg) + 14(4xH) =
Average 56, 4 chances to crit (or miss)

GFB, Shillelagh:
4d8 + 5(CHA) + 3.5(H) + 5(Rad Soul) + 1d8(Imp Smite) + 2(Duel) = 38 to 1 enemy
w/ second enemy: add 3d8 + 5 = 18.5
Average 56.5 across 2 enemies, only 1 chance to crit (or miss)

PAM, 3 attacks
1d8 + 5(CHA) + 3.5(H) + 1d8(Imp Smite) + 2(Duel) = 19.5
1d8 + 5(CHA) + 3.5(H) + 1d8(Imp Smite) + 2(Duel) = 19.5
BA: 1d4 + 5(CHA) + 3.5(H) + 1d8(Imp Smite) + 2(Duel) = 17.5
Average 56.5, 3 chances to crit (or miss)

Any corrections to the math? Thoughts on oath and other choices? What’s a recommended level progression and order of ASI/Feats? Invocations, etc…