No matter what, nothing will stop me from playing a Githyanki monk!! Nothing!!!!! Unless someone blows my mind with a cool build for a Githyanki infiltrator which is not just 'pick rogue'
No reason not to so long as you can put your +2 in DEX and +1 in WIS.
There are a couple of other races that are marginally better (e.g. +3m base movement or +1 hp per level) but it's only really the ASIs that make a significant difference. But try and get proficiency in Perception if you can.
Githyanki actually get one free skill proficiency from the whole pool.
Best thing about them. Perception is ever so useful with a high wisdom, especially on a scout, which monks should be good at, as they tend to be stealthy and have better survivability than rogues if spotted. But Perception is not on their class skill list, and there aren't many backgrounds that grant it either. I don't think any do in BG3.
