keep in mind you can likely heat the steel plate with a torch before bending to make it easier. I think even a modest temperature (not glowing) should make it easier to bend. For certain parts, it might be totally acceptable to bend red hot stuff if you make a notch to indicate where it needs to be and act quick. So long its not too wide, I suspect if the machine has some clearance, you can bend some impressively thick objects. Bending less wide objects in a vise with a torch is pretty damn good too, you can go pretty heavy.
For instance I easily bent a 3/8 inch rod for a handle (bent a [ shape and threaded both ends, so I can put 4 nyloc nuts on it to act as a handle for a variac with only a vise and a torch, but it takes some practice... I used my intuition and 3d skills to make a handle, and I even got it to go into existing chassis holes, but if you lack the skill, bend first and then put paint or marking fluid on the bent object to figure out where to drill the holes. For alot of stuff its not super critical where they are. I like that handle alot compared to using a cabinet handle, its really strong. Someone with bigger skills and an anvil could make a even better handle by bending a more complex shape that has flattened ends and can be drilled to mount with regular bolts, but I try not to get too involved into making super duper hardware, its practical and good enough for me to just attach it with 4 nuts.
Steel gets softer starting at 180c to 600c depending on alloy.