Jumping in here since i actually went the Tilta route first and was pretty disappointed. Specifically, the Tilta Full Camera Cage for Sony FX30 V2 Black looked sleek, but i had issues with the top handle clearance when using my audio gear. It's not as good as expected for a travel doc setup where you need fast access. For a cost-effective gimbal that handles the Sigma 18-50 well, look at the Zhiyun Weebill 3S Handheld Gimbal Stabilizer. It's methodical in its build, though the software isn't as polished as dji. Quick question tho, what specific audio accessories are you mounting? If you're using the Sony XLR handle with a shotgun mic, the balance point shifts a lot. I found that some cages make it hard to reach the record button once that handle is attached. Its a total headache if you dont plan for that clearance.

Totally agree that SmallRig is a solid pick, but if you want absolute stability, check out the Kondor Blue Sony FX30 FX3 Cage with Top Handle Gray because the build quality is insane. Its fantastic! For the gimbal, the Moza AirCross 3 Professional Kit 3-Axis Gimbal is amazing for travel since it folds down so small. That 3.2kg payload capacity is perfect for the Sigma 18-50 plus you dont have to worry about weight limits!

I've tried many and honestly, the SmallRig Cage for Sony FX30 4183 works perfectly with the original handle. Pair it with the DJI RS 3 Mini 3-Axis Gimbal and you're set.