Congrats on the FX3, its a total beast for video. I have been shooting with Sony for years and honestly, if you are spending most of your time on the DJI RS3, the Sony FE PZ 16-35mm f/4 G is the absolute winner here. I know that f/4 aperture might seem like a compromise compared to the f/2.8 options, but you gotta remember the FX3 has that insane dual base ISO at 12,800. You can basically shoot in a dark room at f/4 and the footage stays incredibly clean. The main reason I recommend the PZ for your specific setup is the internal zoom. Since the lens doesnt physically extend when you change focal lengths, your gimbal balance stays perfect. With the Sony FE 16-35mm f/2.8 GM II, you might feel a slight tug on the motors when you zoom in or out. Plus, the FX3 has a dedicated zoom rocker right by the shutter button that works natively with the PZ motors. Its perfect for adding a slow, cinematic creep during documentary interviews. I have used the Tamron 17-28mm f/2.8 Di III RXD before and while it is light, the autofocus and focus breathing compensation on the native Sony glass is just a step above. For real estate, that extra 1mm on the wide end really matters in tight bathrooms too. Stick with the PZ, your workflow will be much smoother.

I'd actually argue for the Sony FE 16-35mm f2.8 GM II. The f/4 is nice, but you'll need that low-light performance for interiors, plus it balances beautifully on a DJI RS 3.

I totally agree that the power zoom is the way to go. That internal zoom is such a lifesaver because you wont have to re-balance your gimbal every time you change focal lengths. Since the FX3 is so good at high ISO, that f/4 aperture really isnt the limitation people think it is for interiors. Its way more practical and saves you a ton of money.