Recently I have moved away from making chimneys having figured out a roof design that imitates how vikings and other ancient peoples vented smoke from their hearth fires. I simply raise a portion of my roof which creates a gap through which smoke can vent. The heat from the fire source creates a chimney effect, pushing smoke upwards towards the roof. As long as there is enough of a gap in the roof all the smoke will vent.

https://steamcommunity.com/sharedfiles/filedetails/?id=2874976444

The building in the left foreground demonstrates how to adequately vent buildings with internal fire sources. Notice the central raised portion of the roof. This works for everything from hanging braziers to central hearths.