That's not likely to be last more than hours. The problem is that plastic gears are typically nylon, which is a more durable plastic to deal with, but it's also tough to glue. It is 3d printable, but in FDM printers which probably don't have the fine detail capability that is probably needed to get a good tooth shape on a fine pitch gear, so then you'd be looking at a SLA resin printer and the most durable resin you can get your hands on.
Depending on how specialty it is, you may be able to source a replacement from something else (maybe looking at hobby servo motors or something and trying to match thickness/pin count/diameter), but the simplest replacement would of course be a donor unit.