Larian Studios

If you are dead set on multi classing a monk, I suggest going as high as lvl 8, lvl 7 you get evasion and lvl 8 would be your second feat. Monks can apply their DEX and WIS modifier to their AC, if anything You'd be better off multi classing to a cleric or rogue. Druid too I suppose.

For cleric, I'd go War cleric for extra attack
For Rogue I'd go either thief or assassin, thief gets two bonus actions which would mix well with monk
For druid I go for anything with Misty Step for obvious reasons.