Really nice test set up! On the big size but really nice. You do what most of the company is not doing, nice! For the gears by the colour of the printed gears looks like PETG. If thst is the case you need to step up. I would aoggest to go to Nylon or similar. Search for a strong Nylon. I am recently test nylon gear for my CNC mill. I print it at the highest temp the filament allows and then boil it for 30 minutes and leave it cool down in the water. There are several. Articles online about it. For the moment I am using eSUN Nylon, since I already bought it but for instance Polymide CoPa is way stronger. That would be my next choice in case of failure. So far the gears is working well
Here some more printing parameters