(RoW warning, I'm going to speak specifically about products in the US)
Here's a shocking fact most don't think about... If you buy sliders from a US manufacturer (designed and built in the US) for any multitude of off road vehicles, there is a reason a lot of them only sell them in bare steel (or, offer no coating warranty); because when you use them off road (their intended purpose), you'll end up chipping off or damaging whatever outer coating you put on them (whether that is powder coat, rattle can, or bed liner), and at least once a year, you should lay under your truck and touch up those spots (a sheet of cardboard to protect the paintwork and a rattle can of black spray paint works great for this). Same for any steel you add under the vehicle (skid plates, diff guards, etc.).
Side steps are much the same (technically, they live a harder life if you take them off road as they sit even lower than a rock slider generally would). If you're doing thousands of miles (or km's) of gravel/dirt, it should be an expectation that the outer coating will get damaged, and will need periodic touch up.
As far as the actual strength and build quality of the Ineos side steps; they are robust. Will they bend? Absolutely, they aren't intended to take the weight of the vehicle. But they will endure much more than any other factory "side steps" I've seen from the other big-name off-roady SUV manufacturers