If you have FB there are a few DIY Open Baffle groups
Open Baffle Speakers: Question About Materials
I am wondering whether the materials and construction methods used for the frame/baffle of these designs matters. In other words, is it necessary to build the frame/baffle so that it does not vibrate/flex/move in response to driver excursion/vibration? If so, what are some of the popular open baffle designers (Spatial Audio, Pure Audio Project, ETC) doing to mitigate this issue?