Keep getting flat at the same point of the inner tube (outer point) but I can’t find anything wrong with the wheel

Since the hole is on the external side of the tube: Next flat you could report the valve location on the wheel and the rolling direction on the inner tube using a paint marker or some sort of crayon (eg Stabilo Woody), so you can match the hole in the tube with the corresponding location on the wheel. Hopefully it will make it easier to locate the shard of glass or whatever that keeps puncturing your tube.

it could happen due to a defect inner tube, especially 3 holes on the same side.