If you just want to make one, milder curry you could do a sambal on the side. It’s not Thai but it’s big in nearby countries like Malaysia, Indonesia, Singapore etc.
It’s a bit like a much hotter siracha but there are loads of varieties, some have shaved coconut for a bit of texture and sweetness etc.
Edit: forgot to say, sambals have similar flavours to Thai stuff, so lemongrass, chilli, coconut etc. Thought it would compliment nicely even if not strictly traditional.