Hate to tell you this but you chose the worst time of year to come. Google “Burning Season Chiang Mai” - I’d recommend sticking to the south of Thailand, particularly the islands, and then come up around April 10 for Songkran. Punspace is the big coworking space, I’d recommend booking a place in Nimman and trying the various cafes there. Kaweh is a good spot if its not too busy.