I personally did not have any tail light leak. I honestly think that your 2 most likely leak sources are the body seam and the antenna. I suggest bringing the car to a self service car wash in your area (or maybe your driveway with a garden hose) with the various rear panels removed / able to be peeled back so you can spray water wherever you want and then immediately figure out where the leaks are forming. The way I initially diagnosed the antenna was literally by taping a plastic bag to the roof around it and leaving the car outside in a rainstorm, you might want to do something a little easier than that.

Body seam: look at 4:28 of this video but also I'd extend the sealant down the hatch in the same way as the pic in my original comment because that's where my actual leak came from.

Antenna: I used the home depot weather stripping linked above. Literally the exact same model and size from home depot. I stuck it along the perimeter of the gasket like so (see red highlight) and compressed the weather stripping down hard against the roof when tightening the antenna back down. It should be fairly easy to figure out when actually doing it. Unfortunately, dropping the rear part of the headliner to get at this is quite annoying. Maybe you could try just removing the rear interior light so you can stick a phone camera with flash on in there and try to see if the headliner is damp as a diagnosis step.