I don't think there's any real solution to hot and humid except cold food and drinks, wearing less, and airflow.

I guess free-flowing garments help a little.

In places that are known for being hot and humid often you'll find thin cotton clothing that is loose fitting (often muslin-style cloth):

Japan has yukata (thin cotton kimono), in the Malay region they use sarong, in South Asia they use things like dhoti and lungi, in Thailand and the surrounding region they have chong kraben and fisherman pants etc.

I think that lightweight thawbs are probably pretty good for hot humid climates tbh.