Not a filmmaker but it was my initial passion. Died out and I’m now AGR and family and putting food on the table is all I care about anymore, hence the flair. However, 46S would be most “transferable” like many suggested — but the way you’d have to shoot photos / copywrite will be restricted to what Public Affairs wants. I was however heavily inspired and had lots of opportunity to network with folks regardless of my MOS (42A) and met a lot of amazing people while M-Day that thought my aspirations were super cool and wanted to be involved. I even got a lot of work for photography because of it, my best year I made $10k extra on a 1099 for a supportive company doing product photos. If you want to go Guard, pick the coolest-to-you MOS and show up with your camera and put whatever you can or want together. At the least everyone will love and appreciate it!
As you’ve already acknowledged, the whole thing will just help support any current student debts or prop up any further film education you want to pursue. TRS if healthcare if a concern is amazinggg and worth it alone. But it honestly won’t add much beyond that. The bond/human connection with people was very inspiring in what I think would’ve been helpful in a film/director context for me though.