Lacto bacteria are present on many garden vegetable. Last year we made fermented pickles vs pickles made in a vinegar brine. We put cucumbers in a salt brine with spices, and within a few weeks the natural lacto bacteria had converted some of the carbs to lactic acid. The pH was around 3.5. Much more delicious than grocery store pickles, with a significantly different flavor. If you like dill pickles, you should try this! Here is a good article on the science of lacto fermentation:
The Science of Lactic Acid Fermentation: Pickles, Kraut, Kimchi, and More
It is likely that the lacto bateria are destroyed by the process of drying the gesho, so you would need to use fresh gesho or introduce lacto bacteria from another source. I don't know whether raw honey would include lacto bacteria, but it might.
In traditional Tej, the honey probably provides the sugar while the fresh gesho provides the lacto bacteria. My guess is that they boil it after one week to stop the process, so that it doesn't get too acidic and leaves some residual sugars. This two-stage process is interesting to me, so I might need to give it a try. A short stage of lacto fermentation to provide complex flavors, followed by fermentation by wine yeast. I note from the article above that lacto bacteria will tolerate the presence of oxygen, but will only ferment aerobically. So maybe after a few days you could stir vigorously and add wine yeast. It would be an interesting experiment!
@BigDaveK you can add this to your list!