My 2019 Forester Premium doesn't even have a glove box light, so I'd consider yourself lucky that you have one at all. From what I've seen around the forums and elsewhere, it seems that not even the higher model 2019 Forester's have a glove box light. Since the Sport has the additional trunk light, maybe they also added a glove box light.
Whatever the case, I think it's really weird that they left out a glove box light.
I found a diagram that shows the glove box with light, but nothing that really helps you with getting it out to replace the bulb.
Parts departments (like this one - found via a search) seem to have bits and pieces of the the service manual available to help you figure out what part you need.
Well... ignore my last comment. Turns out I do have a glove box light... unlike most cars were the glove box light turns on whether or not the car is on, the glove box light on the Forester seems to only turn on when the engine is running (and presumably in ACC mode - I haven't tested). I'm not thrilled by their choice for when the light turns on. It's also wayyyy too dim. I'm going to see if I can swap it out, too.
Edit: Added photos of glove box light.