So, how silly can you get with party buffs at level 1?
Warforged fighter, defense fighting style, chain+shield.
Two forge clerics both used their class feature on your armor and shield. One casts shield of faith on you, the other used bless. A third cleric or Druid uses resistance. They also marry you and dedicate you (two castings of ceremony).
So now your AC is 26, and you get +3d4 on your first save, 2d4 thereafter.
Multiple changeling warlocks give you magic stones, for 1d6+4 attacks with +6 to hit.
A changeling bard casts heroism on you, for +4 THP
And let's say you've got 15STR, 16 Dex, 16 Con. So 17 HP and +5+2or3d4 Dex saves.
I don't know this guy's DC on the breath attack, but I think this may be good enough to win head-on.
Your DPR is (7.5)/2 + 11/20 = 4.3DPR, so you kill him in ~ 13 rounds on average.
His DPA against you is 11/20 = 0.55, killing you in ~ 30 attacks on average, which is basically 14 rounds.
So, on average, you win. Though it's really really swingy.