Assuming you can't, and the quicken is to put out an EB:
At level 5 (practical):
Scorching Ray + EB + Hex + HexCurse + 2xAgonizing Blast = 6d6+2d10+5d6+15+10 = 74/75
vs
EB x2 + Hex + HexCurse + 4xAgonizing Blast = 4d10+4d6+12+20 = 68
The main issue is you're spending spell points AND spell slots, at least doubling your use of resources to get that extra 6-7 average damage in a round.
That's what I meant. You can choose to have Wish at level 19+, or you can have Action Surge to cast two levelled spells from level... 8? +.You can't get Wish period because it requires Sorc level 17 at a minimum to access level 9 spell slots. Warlock is NOT considered a spellcasting class and does not benefit from the multiclass spell slot table.
You would only get up to level 5 spells slots going 9 sorc/9 warlock/2 fighter. You need a minimum of level 17 in sorc to access lvl 9 spells.
You either have to choose action surge or Wish.
That's what I meant. You can choose to have Wish at level 19+, or you can have Action Surge to cast two levelled spells from level... 8? +.
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Considering a non-dead enemy means more attacks against you, more chance to escape, etc. ...What level do you want?
My point would still be the same, if you're planning on shooting a 9th level Scorching Ray and quickening an EB you're still burning resources at a very high rate.
At level 20:
Scorching Ray lvl9 + EB + Hex + HexCurse + 4xAgonizing Blast =10d6+4d10+14d6+84+20 = 210
EB x2 + Hex + HexCurse + 8xAgonizing Blast = 8d10+8d6+48+40 = 160
Is 50 extra dmg worth a 9th level slot...? good question. It's a battle of expending resources for quick dmg vs consistent high dmg without huge expenditure.
Considering a non-dead enemy means more attacks against you, more chance to escape, etc. ...
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Certainly. And if there is a big bad there, pour EVERYTHING at him. But if we're talking about an everyday campaign set of encounters, then blowing your 9th level slot quicky just to one-shot that purple worm (etc), and only be able to get it back over tactful short rests trading warlock slots for spell points for sorcerer slots.
Burning so many resources so quickly is a big risk.